how do we know global warming is real essay

What evidence exists that Earth is warming and that humans are the main cause?

We know the world is warming because people have been recording daily high and low temperatures at thousands of weather stations worldwide, over land and ocean, for many decades and, in some locations, for more than a century. When different teams of climate scientists in different agencies (e.g., NOAA and NASA) and in other countries (e.g., the U.K.’s Hadley Centre) average these data together, they all find essentially the same result: Earth’s average surface temperature has risen by about 1.8°F (1.0°C) since 1880. 

( bar chart ) Yearly temperature compared to the twentieth-century average from 1850–2023. Red bars mean warmer-than-average years; blue bars mean colder-than-average years. (line graph) Atmospheric carbon dioxide amounts: 1850-1958 from IAC , 1959-2023 from NOAA Global Monitoring Lab . NOAA Climate.gov graph, adapted from original by Dr. Howard Diamond (NOAA ARL).

In addition to our surface station data, we have many different lines of evidence that Earth is warming ( learn more ). Birds are migrating earlier, and their migration patterns are changing.  Lobsters  and  other marine species  are moving north. Plants are blooming earlier in the spring. Mountain glaciers are melting worldwide, and snow cover is declining in the Northern Hemisphere (Learn more  here  and  here ). Greenland’s ice sheet—which holds about 8 percent of Earth’s fresh water—is melting at an accelerating rate ( learn more ). Mean global sea level is rising ( learn more ). Arctic sea ice is declining rapidly in both thickness and extent ( learn more ).

The Greenland Ice Sheet lost mass again in 2020, but not as much as it did 2019. Adapted from the 2020 Arctic Report Card, this graph tracks Greenland mass loss measured by NASA's GRACE satellite missions since 2002. The background photo shows a glacier calving front in western Greenland, captured from an airplane during a NASA Operation IceBridge field campaign. Full story.

We know this warming is largely caused by human activities because the key role that carbon dioxide plays in maintaining Earth’s natural greenhouse effect has been understood since the mid-1800s. Unless it is offset by some equally large cooling influence, more atmospheric carbon dioxide will lead to warmer surface temperatures. Since 1800, the amount of carbon dioxide in the atmosphere  has increased  from about 280 parts per million to 410 ppm in 2019. We know from both its rapid increase and its isotopic “fingerprint” that the source of this new carbon dioxide is fossil fuels, and not natural sources like forest fires, volcanoes, or outgassing from the ocean.

Philip James de Loutherbourg's 1801 painting, Coalbrookdale by Night , came to symbolize the start of the Industrial Revolution, when humans began to harness the power of fossil fuels—and to contribute significantly to Earth's atmospheric greenhouse gas composition. Image from Wikipedia .

Finally, no other known climate influences have changed enough to account for the observed warming trend. Taken together, these and other lines of evidence point squarely to human activities as the cause of recent global warming.

USGCRP (2017). Climate Science Special Report: Fourth National Climate Assessment, Volume 1 [Wuebbles, D.J., D.W. Fahey, K.A. Hibbard, D.J. Dokken, B.C. Stewart, and T.K. Maycock (eds.)]. U.S. Global Change Research Program, Washington, DC, USA, 470 pp, doi:  10.7930/J0J964J6 .

National Fish, Wildlife, and Plants Climate Adaptation Partnership (2012):  National Fish, Wildlife, and Plants Climate Adaptation Strategy . Association of Fish and Wildlife Agencies, Council on Environmental Quality, Great Lakes Indian Fish and Wildlife Commission, National Oceanic and Atmospheric Administration, and U.S. Fish and Wildlife Service. Washington, D.C. DOI: 10.3996/082012-FWSReport-1

IPCC (2019). Summary for Policymakers. In: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate. [H.-O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.)]. In press.

NASA JPL: "Consensus: 97% of climate scientists agree."  Global Climate Change . A website at NASA's Jet Propulsion Laboratory (climate.nasa.gov/scientific-consensus). (Accessed July 2013.)

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There is unequivocal evidence that Earth is warming at an unprecedented rate. Human activity is the principal cause.

• While Earth’s climate has changed throughout its history , the current warming is happening at a rate not seen in the past 10,000 years.
• According to the Intergovernmental Panel on Climate Change ( IPCC ), "Since systematic scientific assessments began in the 1970s, the influence of human activity on the warming of the climate system has evolved from theory to established fact." 1
• Scientific information taken from natural sources (such as ice cores, rocks, and tree rings) and from modern equipment (like satellites and instruments) all show the signs of a changing climate.
• From global temperature rise to melting ice sheets, the evidence of a warming planet abounds.

The rate of change since the mid-20th century is unprecedented over millennia.

Earth's climate has changed throughout history. Just in the last 800,000 years, there have been eight cycles of ice ages and warmer periods, with the end of the last ice age about 11,700 years ago marking the beginning of the modern climate era — and of human civilization. Most of these climate changes are attributed to very small variations in Earth’s orbit that change the amount of solar energy our planet receives.

The current warming trend is different because it is clearly the result of human activities since the mid-1800s, and is proceeding at a rate not seen over many recent millennia. 1 It is undeniable that human activities have produced the atmospheric gases that have trapped more of the Sun’s energy in the Earth system. This extra energy has warmed the atmosphere, ocean, and land, and widespread and rapid changes in the atmosphere, ocean, cryosphere, and biosphere have occurred.

Earth-orbiting satellites and new technologies have helped scientists see the big picture, collecting many different types of information about our planet and its climate all over the world. These data, collected over many years, reveal the signs and patterns of a changing climate.

Scientists demonstrated the heat-trapping nature of carbon dioxide and other gases in the mid-19th century. 2 Many of the science instruments NASA uses to study our climate focus on how these gases affect the movement of infrared radiation through the atmosphere. From the measured impacts of increases in these gases, there is no question that increased greenhouse gas levels warm Earth in response.

Scientific evidence for warming of the climate system is unequivocal.

Intergovernmental Panel on Climate Change

Ice cores drawn from Greenland, Antarctica, and tropical mountain glaciers show that Earth’s climate responds to changes in greenhouse gas levels. Ancient evidence can also be found in tree rings, ocean sediments, coral reefs, and layers of sedimentary rocks. This ancient, or paleoclimate, evidence reveals that current warming is occurring roughly 10 times faster than the average rate of warming after an ice age. Carbon dioxide from human activities is increasing about 250 times faster than it did from natural sources after the last Ice Age. 3

The Evidence for Rapid Climate Change Is Compelling:

Global Temperature Is Rising

The planet's average surface temperature has risen about 2 degrees Fahrenheit (1 degrees Celsius) since the late 19th century, a change driven largely by increased carbon dioxide emissions into the atmosphere and other human activities. 4 Most of the warming occurred in the past 40 years, with the seven most recent years being the warmest. The years 2016 and 2020 are tied for the warmest year on record. 5 Image credit: Ashwin Kumar, Creative Commons Attribution-Share Alike 2.0 Generic.

The Ocean Is Getting Warmer

The ocean has absorbed much of this increased heat, with the top 100 meters (about 328 feet) of ocean showing warming of 0.67 degrees Fahrenheit (0.33 degrees Celsius) since 1969. 6 Earth stores 90% of the extra energy in the ocean. Image credit: Kelsey Roberts/USGS

The Ice Sheets Are Shrinking

The Greenland and Antarctic ice sheets have decreased in mass. Data from NASA's Gravity Recovery and Climate Experiment show Greenland lost an average of 279 billion tons of ice per year between 1993 and 2019, while Antarctica lost about 148 billion tons of ice per year. 7 Image: The Antarctic Peninsula, Credit: NASA

Glaciers Are Retreating

Glaciers are retreating almost everywhere around the world — including in the Alps, Himalayas, Andes, Rockies, Alaska, and Africa. 8 Image: Miles Glacier, Alaska Image credit: NASA

Snow Cover Is Decreasing

Satellite observations reveal that the amount of spring snow cover in the Northern Hemisphere has decreased over the past five decades and the snow is melting earlier. 9 Image credit: NASA/JPL-Caltech

Sea Level Is Rising

Global sea level rose about 8 inches (20 centimeters) in the last century. The rate in the last two decades, however, is nearly double that of the last century and accelerating slightly every year. 10 Image credit: U.S. Army Corps of Engineers Norfolk District

Arctic Sea Ice Is Declining

Both the extent and thickness of Arctic sea ice has declined rapidly over the last several decades. 11 Credit: NASA's Scientific Visualization Studio

Extreme Events Are Increasing in Frequency

The number of record high temperature events in the United States has been increasing, while the number of record low temperature events has been decreasing, since 1950. The U.S. has also witnessed increasing numbers of intense rainfall events. 12 Image credit: Régine Fabri,  CC BY-SA 4.0 , via Wikimedia Commons

Ocean Acidification Is Increasing

Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30%. 13 , 14 This increase is due to humans emitting more carbon dioxide into the atmosphere and hence more being absorbed into the ocean. The ocean has absorbed between 20% and 30% of total anthropogenic carbon dioxide emissions in recent decades (7.2 to 10.8 billion metric tons per year). 1 5 , 16 Image credit: NOAA

1. IPCC Sixth Assessment Report, WGI, Technical Summary . B.D. Santer et.al., “A search for human influences on the thermal structure of the atmosphere.” Nature 382 (04 July 1996): 39-46. https://doi.org/10.1038/382039a0. Gabriele C. Hegerl et al., “Detecting Greenhouse-Gas-Induced Climate Change with an Optimal Fingerprint Method.” Journal of Climate 9 (October 1996): 2281-2306. https://doi.org/10.1175/1520-0442(1996)009<2281:DGGICC>2.0.CO;2. V. Ramaswamy, et al., “Anthropogenic and Natural Influences in the Evolution of Lower Stratospheric Cooling.” Science 311 (24 February 2006): 1138-1141. https://doi.org/10.1126/science.1122587. B.D. Santer et al., “Contributions of Anthropogenic and Natural Forcing to Recent Tropopause Height Changes.” Science 301 (25 July 2003): 479-483. https://doi.org/10.1126/science.1084123. T. Westerhold et al., "An astronomically dated record of Earth’s climate and its predictability over the last 66 million years." Science 369 (11 Sept. 2020): 1383-1387. https://doi.org/10.1126/science.1094123

2. In 1824, Joseph Fourier calculated that an Earth-sized planet, at our distance from the Sun, ought to be much colder. He suggested something in the atmosphere must be acting like an insulating blanket. In 1856, Eunice Foote discovered that blanket, showing that carbon dioxide and water vapor in Earth's atmosphere trap escaping infrared (heat) radiation. In the 1860s, physicist John Tyndall recognized Earth's natural greenhouse effect and suggested that slight changes in the atmospheric composition could bring about climatic variations. In 1896, a seminal paper by Swedish scientist Svante Arrhenius first predicted that changes in atmospheric carbon dioxide levels could substantially alter the surface temperature through the greenhouse effect. In 1938, Guy Callendar connected carbon dioxide increases in Earth’s atmosphere to global warming. In 1941, Milutin Milankovic linked ice ages to Earth’s orbital characteristics. Gilbert Plass formulated the Carbon Dioxide Theory of Climate Change in 1956.

3. IPCC Sixth Assessment Report, WG1, Chapter 2 Vostok ice core data; NOAA Mauna Loa CO2 record O. Gaffney, W. Steffen, "The Anthropocene Equation." The Anthropocene Review 4, issue 1 (April 2017): 53-61. https://doi.org/abs/10.1177/2053019616688022.

4. https://www.ncei.noaa.gov/monitoring https://crudata.uea.ac.uk/cru/data/temperature/ http://data.giss.nasa.gov/gistemp

5. https://www.giss.nasa.gov/research/news/20170118/

6. S. Levitus, J. Antonov, T. Boyer, O Baranova, H. Garcia, R. Locarnini, A. Mishonov, J. Reagan, D. Seidov, E. Yarosh, M. Zweng, " NCEI ocean heat content, temperature anomalies, salinity anomalies, thermosteric sea level anomalies, halosteric sea level anomalies, and total steric sea level anomalies from 1955 to present calculated from in situ oceanographic subsurface profile data (NCEI Accession 0164586), Version 4.4. (2017) NOAA National Centers for Environmental Information. https://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/index3.html K. von Schuckmann, L. Cheng, L,. D. Palmer, J. Hansen, C. Tassone, V. Aich, S. Adusumilli, H. Beltrami, H., T. Boyer, F. Cuesta-Valero, D. Desbruyeres, C. Domingues, A. Garcia-Garcia, P. Gentine, J. Gilson, M. Gorfer, L. Haimberger, M. Ishii, M., G. Johnson, R. Killick, B. King, G. Kirchengast, N. Kolodziejczyk, J. Lyman, B. Marzeion, M. Mayer, M. Monier, D. Monselesan, S. Purkey, D. Roemmich, A. Schweiger, S. Seneviratne, A. Shepherd, D. Slater, A. Steiner, F. Straneo, M.L. Timmermans, S. Wijffels. "Heat stored in the Earth system: where does the energy go?" Earth System Science Data 12, Issue 3 (07 September 2020): 2013-2041. https://doi.org/10.5194/essd-12-2013-2020.

7. I. Velicogna, Yara Mohajerani, A. Geruo, F. Landerer, J. Mouginot, B. Noel, E. Rignot, T. Sutterly, M. van den Broeke, M. Wessem, D. Wiese, "Continuity of Ice Sheet Mass Loss in Greenland and Antarctica From the GRACE and GRACE Follow-On Missions." Geophysical Research Letters 47, Issue 8 (28 April 2020): e2020GL087291. https://doi.org/10.1029/2020GL087291.

8. National Snow and Ice Data Center World Glacier Monitoring Service

9. National Snow and Ice Data Center D.A. Robinson, D. K. Hall, and T. L. Mote, "MEaSUREs Northern Hemisphere Terrestrial Snow Cover Extent Daily 25km EASE-Grid 2.0, Version 1 (2017). Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/MEASURES/CRYOSPHERE/nsidc-0530.001 . http://nsidc.org/cryosphere/sotc/snow_extent.html Rutgers University Global Snow Lab. Data History

10. R.S. Nerem, B.D. Beckley, J. T. Fasullo, B.D. Hamlington, D. Masters, and G.T. Mitchum, "Climate-change–driven accelerated sea-level rise detected in the altimeter era." PNAS 15, no. 9 (12 Feb. 2018): 2022-2025. https://doi.org/10.1073/pnas.1717312115.

11. https://nsidc.org/cryosphere/sotc/sea_ice.html Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS, Zhang and Rothrock, 2003) http://psc.apl.washington.edu/research/projects/arctic-sea-ice-volume-anomaly/ http://psc.apl.uw.edu/research/projects/projections-of-an-ice-diminished-arctic-ocean/

12. USGCRP, 2017: Climate Science Special Report: Fourth National Climate Assessment, Volume I [Wuebbles, D.J., D.W. Fahey, K.A. Hibbard, D.J. Dokken, B.C. Stewart, and T.K. Maycock (eds.)]. U.S. Global Change Research Program, Washington, DC, USA, 470 pp, https://doi.org/10.7930/j0j964j6 .

13. http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F

14. http://www.pmel.noaa.gov/co2/story/Ocean+Acidification

15. C.L. Sabine, et al., “The Oceanic Sink for Anthropogenic CO2.” Science 305 (16 July 2004): 367-371. https://doi.org/10.1126/science.1097403.

16. Special Report on the Ocean and Cryosphere in a Changing Climate , Technical Summary, Chapter TS.5, Changing Ocean, Marine Ecosystems, and Dependent Communities, Section 5.2.2.3. https://www.ipcc.ch/srocc/chapter/technical-summary/

Header image shows clouds imitating mountains as the sun sets after midnight as seen from Denali's backcountry Unit 13 on June 14, 2019. Credit: NPS/Emily Mesner Image credit in list of evidence: Ashwin Kumar, Creative Commons Attribution-Share Alike 2.0 Generic.

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Analysis: Why scientists think 100% of global warming is due to humans

Zeke Hausfather

The extent of the human contribution to modern global warming is a hotly debated topic in political circles, particularly in the US.

During a recent congressional hearing, Rick Perry, the US energy secretary, remarked that “to stand up and say that 100% of global warming is because of human activity, I think on its face, is just indefensible”.

However, the science on the human contribution to modern warming is quite clear. Humans emissions and activities have caused around 100% of the warming observed since 1950, according to the Intergovernmental Panel on Climate Change’s (IPCC) fifth assessment report .

Here Carbon Brief examines how each of the major factors affecting the Earth’s climate would influence temperatures in isolation – and how their combined effects almost perfectly predict long-term changes in the global temperature.

Carbon Brief’s analysis finds that:

• Since 1850, almost all the long-term warming can be explained by greenhouse gas emissions and other human activities.
• If greenhouse gas emissions alone were warming the planet, we would expect to see about a third more warming than has actually occurred. They are offset by cooling from human-produced atmospheric aerosols.
• Aerosols are projected to decline significantly by 2100 , bringing total warming from all factors closer to warming from greenhouse gases alone.
• Natural variability in the Earth’s climate is unlikely to play a major role in long-term warming.

How much warming is caused by humans?

In its 2013 fifth assessment report, the IPCC stated in its summary for policymakers that it is “extremely likely that more than half of the observed increase in global average surface temperature” from 1951 to 2010 was caused by human activity. By “extremely likely”, it meant that there was between a 95% and 100% probability that more than half of modern warming was due to humans.

This somewhat convoluted statement has been often misinterpreted as implying that the human responsibility for modern warming lies somewhere between 50% and 100%. In fact, as NASA’s Dr Gavin Schmidt has pointed out, the IPCC’s implied best guess was that humans were responsible for around 110% of observed warming (ranging from 72% to 146%), with natural factors in isolation leading to a slight cooling over the past 50 years.

Similarly, the recent US fourth national climate assessment found that between 93% to 123% of observed 1951-2010 warming was due to human activities.

These conclusions have led to some confusion as to how more than 100% of observed warming could be attributable to human activity. A human contribution of greater than 100% is possible because natural climate change associated with volcanoes and solar activity would most likely have resulted in a slight cooling over the past 50 years, offsetting some of the warming associated with human activities.

‘Forcings’ that change the climate

Scientists measure the various factors that affect the amount of energy that reaches and remains in the Earth’s climate. They are known as “radiative forcings”.

These forcings include greenhouse gases, which trap outgoing heat, aerosols – both from human activities and volcanic eruptions – that reflect incoming sunlight and influence cloud formation, changes in solar output, changes in the reflectivity of the Earth’s surface associated with land use, and many other factors.

To assess the role of each different forcing in observed temperature changes, Carbon Brief adapted a simple statistical climate model developed by Dr Karsten Haustein and his colleagues at the University of Oxford and University of Leeds . This model finds the relationship between both human and natural climate forcings and temperature that best matches observed temperatures, both globally and over land areas only.

The figure below shows the estimated role of each different climate forcing in changing global surface temperatures since records began in 1850 – including greenhouse gases (red line), aerosols (dark blue), land use (light blue), ozone (pink), solar (yellow) and volcanoes (orange).

The black dots show observed temperatures from the Berkeley Earth surface temperature project, while the grey line shows the estimated warming from the combination of all the different types of forcings.

The combination of all radiative forcings generally matches longer-term changes in observed temperatures quite well. There is some year-to-year variability, primarily from El Niño events , that is not driven by changes in forcings. There are also periods from 1900-1920 and 1930-1950 where some larger disagreements are evident between projected and observed warming, both in this simple model and in more complex climate models .

The chart highlights that, of all the radiative forcings analysed, only increases in greenhouse gas emissions produce the magnitude of warming experienced over the past 150 years.

If greenhouse gas emissions alone were warming the planet, we would expect to see about a third more warming than has actually occurred.

So, what roles do all the other factors play?

• Q&A: How do climate models work?
• Interactive: The impacts of climate change at 1.5C, 2C and beyond
• Explainer: How scientists estimate ‘climate sensitivity’
• Mapped: How every part of the world has warmed – and could continue to warm

The extra warming from greenhouse gases is being offset by sulphur dioxide and other products of fossil fuel combustion that form atmospheric aerosols . Aerosols in the atmosphere both reflect incoming solar radiation back into space and increase the formation of high, reflective clouds, cooling the Earth.

Ozone is a short-lived greenhouse gas that traps outgoing heat and warms the Earth. Ozone is not emitted directly, but is formed when methane, carbon monoxide, nitrogen oxides and volatile organic compounds break down in the atmosphere. Increases in ozone are directly attributable to human emissions of these gases.

In the upper atmosphere, reductions in ozone associated with chlorofluorocarbons (CFCs) and other halocarbons depleting the ozone layer have had a modest cooling effect. The net effects of combined lower and upper atmospheric ozone changes have modestly warmed the Earth by a few tenths of a degree.

Changes in the way land is used alter the reflectivity of the Earth’s surface. For example, replacing a forest with a field will generally increase the amount of sunlight reflected back into space, particularly in snowy regions. The net climate effect of land-use changes since 1850 is a modest cooling.

Volcanoes have a short-term cooling effect on the climate due to their injection of sulphate aerosols high into the stratosphere, where they can remain aloft for a few years, reflecting incoming sunlight back into space. However, once the sulphates drift back down to the surface, the cooling effect of volcanoes goes away. The orange line shows the estimated impact of volcanoes on the climate, with large downward spikes in temperatures of up to 0.4C associated with major eruptions.

Finally, solar activity is measured by satellites over the past few decades and estimated based on sunspot counts in the more distant past. The amount of energy reaching the Earth from the sun fluctuates modestly on a cycle of around 11 years. There has been a slight increase in overall solar activity since the 1850s, but the amount of additional solar energy reaching the Earth is small compared to other radiative forcings examined.

Over the past 50 years, solar energy reaching the Earth has actually declined slightly , while temperatures have increased dramatically.

Human forcings match observed warming

The accuracy of this model depends on the accuracy of the radiative forcing estimates. Some types of radiative forcing like that from atmospheric CO2 concentrations can be directly measured and have relatively small uncertainties. Others, such as aerosols, are subject to much greater uncertainties due to the difficulty of accurately measuring their effects on cloud formation.

These are accounted for in the figure below, which shows combined natural forcings (blue line) and human forcings (red line) and the uncertainties that the statistical model associates with each. These shaded areas are based on 200 different estimates of radiative forcings, incorporating research attempting to estimate a range of values for each. Uncertainties in human factors increase after 1960, driven largely by increases in aerosol emissions after that point.

Overall, warming associated with all human forcings agrees quite well with observed warming, showing that about 104% of the total since the start of the “modern” period in 1950 comes from human activities (and 103% since 1850), which is similar to the value reported by the IPCC. Combined natural forcings show a modest cooling, primarily driven by volcanic eruptions.

The simple statistical model used for this analysis by Carbon Brief differs from much more complex climate models generally used by scientists to assess the human fingerprint on warming. Climate models do not simply “fit” forcings to observed temperatures. Climate models also include variations in temperature over space and time, and can account for different efficacies of radiative forcings in different regions of the Earth.

However, when analysing the impact of different forcings on global temperatures, complex climate models generally find results similar to simple statistical models. The figure below, from the IPCC’s Fifth Assessment Report, shows the influence of different factors on temperature for the period from 1950 to 2010. Observed temperatures are shown in black, while the sum of human forcings is shown in orange.

This suggests that human forcings alone would have resulted in approximately 110% of observed warming . The IPCC also included the estimated magnitude of internal variability over that period in the models, which they suggest is relatively small and comparable to that of natural forcings.

As Prof Gabi Hegerl at the University of Edinburgh tells Carbon Brief: “The IPCC report has an estimate that basically says the best guess is no contribution [from natural variability] with not that much uncertainty.”

Land areas are warming faster

Land temperatures have warmed considerably faster than average global temperatures over the past century, with temperatures reaching around 1.7C above pre-industrial levels in recent years. The land temperature record also goes back further in time than the global temperature record, though the period prior to 1850 is subject to much greater uncertainties .

Both human and natural radiative forcings can be matched to land temperatures using the statistical model. The magnitude of human and natural forcings will differ a bit between land and global temperatures. For example, volcanic eruptions appear to have a larger influence on land, as land temperatures are likely to respond faster to rapid changes in forcings.

The figure below shows the relative contribution of each different radiative forcing to land temperatures since 1750.

The combination of all forcings generally matches observed temperatures quite well, with short-term variability around the grey line primarily driven by El Niño and La Niña events. There is a wider variation in temperatures prior to 1850, reflecting the much larger uncertainties in the observational records that far back.

There is still a period around 1930 and 1940 where observations exceed what the model predicts, though the differences are less pronounced than in global temperatures and the 1900-1920 divergence is mostly absent in land records.

Volcanic eruptions in the late 1700s and early 1800s stand out sharply in the land record. The eruption of Mount Tambora in Indonesia in 1815 may have cooled land temperatures by a massive 1.5C, though records at the time were limited to parts of the Northern Hemisphere and it is, therefore, hard to draw a firm conclusion about global impacts. In general, volcanoes appear to cool land temperatures by nearly twice as much as global temperatures.

What may happen in the future?

Carbon Brief used the same model to project future temperature changes associated with each forcing factor. The figure below shows observations up to 2017, along with future post-2017 radiative forcings from RCP6.0 , a medium-to-high future warming scenario.

When provided with the radiative forcings for the RCP6.0 scenario, the simple statistical model shows warming of around 3C by 2100, nearly identical to the average warming that climate models find.

Future radiative forcing from CO2 is expected to continue to increase if emissions rise. Aerosols, on the other hand, are projected to peak at today’s levels and decline significantly by 2100 , driven in large part by concerns about air quality. This reduction in aerosols will enhance overall warming, bringing total warming from all radiative forcing closer to warming from greenhouse gases alone. The RCP scenarios assume no specific future volcanic eruptions, as the timing of these is unknowable, while solar output continues its 11-year cycle.

This approach can also be applied to land temperatures, as shown in the figure below. Here, land temperatures are shown between 1750 and 2100, with post-2017 forcings also from RCP6.0.

The land is expected to warm about 30% faster than the globe as a whole, as the rate of warming over the oceans is buffered by ocean heat uptake. This is seen in the model results, where land warms by around 4C by 2100 compared to 3C globally in the RCP6.0 scenario.

There is a wide range of future warming possible from different RCP scenarios and different values for the sensitivity of the climate system , but all show a similar pattern of declining future aerosol emissions and a larger role for greenhouse gas forcing in future temperatures.

The role of natural variability

While natural forcings from solar and volcanoes do not seem to play much of a role in long-term warming, there is also natural variability associated with ocean cycles and variations in ocean heat uptake.

As the vast majority of energy trapped by greenhouse gases is absorbed by the oceans rather than the atmosphere, changes in the rate of ocean heat uptake can potentially have large impacts on the surface temperature. Some researchers have argued that multidecadal cycles, such as the Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO), can play a role in warming at a decadal scale.

While human factors explain all the long-term warming, there are some specific periods that appear to have warmed or cooled faster than can be explained based on our best estimates of radiative forcing. For example, the modest mismatch between the radiative forcing-based estimate and observations during the mid-1900s might be evidence of a role for natural variability during that period.

A number of researchers have examined the potential for natural variability to impact long-term warming trends. They have found that it generally plays a limited role. For example, Dr Markus Huber and Dr Reto Knutti at the Institute for Atmospheric and Climate Science (IAC) in Zurich found a maximum possible contribution of natural variability of around 26% (+/- 12%) over the past 100 years and 18% (+/- 9%) over the past 50 years.

Knutti tells Carbon Brief:

“We can never completely rule out that natural variability is larger than we currently think. But that is a weak argument: you can, of course, never rule out the unknown unknown. The question is whether there is strong, or even any evidence for it. And the answer is no, in my view.

Models get the short-term temperature variability approximately right. In many cases, they even have too much. And for the long term, we can’t be sure because the observations are limited. But the forced response pretty much explains the observations, so there is no evidence from the 20th century that we are missing something…

Even if models were found to underestimate internal variability by a factor of three, it is extremely unlikely [less than 5% chance] that internal variability could produce a trend as large as observed.”

Similarly, Dr Martin Stolpe and colleagues, also at IAC, recently analysed the role of multidecadal natural variability in both the Atlantic and Pacific oceans. They found that “less than 10% of the observed global warming during the second half of the 20th century is caused by internal variability in these two ocean basins, reinforcing the attribution of most of the observed warming to anthropogenic forcings”.

Internal variability is likely to have a much larger role in regional temperatures. For example, in producing unusually warm periods in the Arctic and the US in the 1930s. However, its role in influencing long-term changes in global surface temperatures appears to be limited.

While there are natural factors that affect the Earth’s climate, the combined influence of volcanoes and changes in solar activity would have resulted in cooling rather than warming over the past 50 years.

The global warming witnessed over the past 150 years matches nearly perfectly what is expected from greenhouse gas emissions and other human activity, both in the simple model examined here and in more complex climate models. The best estimate of the human contribution to modern warming is around 100%.

Some uncertainty remains due to the role of natural variability, but researchers suggest that ocean fluctuations and similar factors are unlikely to be the cause of more than a small fraction of modern global warming.

Methodology

The simple statistical model used in this article is adapted from the Global Warming Index published by Haustein et al ( 2017 ). In turn, it is based on the Otto et al ( 2015 ) model.

The model estimates contributions to observed climate change and removes the impact of natural year-to-year fluctuations by a multiple linear regression of observed temperatures and estimated responses to total human-induced and total natural drivers of climate change. The forcing responses are provided by the standard simple climate model given in Chapter 8 of IPCC ( 2013 ), but the size of these responses is estimated by the fit to the observations. The forcings are based on IPCC (2013) values and were updated to 2017 using data from NOAA and ECLIPSE . 200 variations of these forcings were provided by Dr. Piers Forster  of the University of Leeds , reflecting the uncertainty in forcing estimates. An Excel spreadsheet containing their model is also provided.

The model was adapted by calculating forcing responses for each of the different major climate forcings rather than simply total human and natural forcings, using the Berkeley Earth record for observations. The decay time of thermal response used in converting forcings to forcing responses was adjusted to be one year rather than four years for volcanic forcings to better reflect the fast response time present in observations. The effects of El Niño and La Niña (ENSO) events was removed from the observations using an approach adapted from Foster and Rahmstorf ( 2011 ) and the Kaplan El Niño 3.4 index when calculating the volcanic temperature response, as the overlap between volcanoes and ENSO otherwise complicates empirical estimates.

The temperature response for each individual forcing was calculated by scaling their forcing responses by the total human or natural coefficients from the regression model . The regression model was also run separately for land temperatures. Temperature responses for each forcing between 2018 and 2100 were estimated using forcing data from RCP6.0, normalised to match the magnitude of observed forcings at the end of 2017.

Uncertainties in total human and total natural temperature response was estimated using a Monte Carlo analysis of 200 different forcing series, as well as the uncertainties in the estimated regression coefficients. The Python code used to run the model is archived with GitHub and available for download .

Observational data from 2017 shown in the figures is based on the average of the first 10 months of the year and is likely to be quite similar to the ultimate annual value.

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Human activity affects global surface temperatures by changing Earth ’s radiative balance—the “give and take” between what comes in during the day and what Earth emits at night. Increases in greenhouse gases —i.e., trace gases such as carbon dioxide and methane that absorb heat energy emitted from Earth’s surface and reradiate it back—generated by industry and transportation cause the atmosphere to retain more heat, which increases temperatures and alters precipitation patterns.

Global warming, the phenomenon of increasing average air temperatures near Earth’s surface over the past one to two centuries, happens mostly in the troposphere , the lowest level of the atmosphere, which extends from Earth’s surface up to a height of 6–11 miles. This layer contains most of Earth’s clouds and is where living things and their habitats and weather primarily occur.

Continued global warming is expected to impact everything from energy use to water availability to crop productivity throughout the world. Poor countries and communities with limited abilities to adapt to these changes are expected to suffer disproportionately. Global warming is already being associated with increases in the incidence of severe and extreme weather, heavy flooding , and wildfires —phenomena that threaten homes, dams, transportation networks, and other facets of human infrastructure. Learn more about how the IPCC’s Sixth Assessment Report, released in 2021, describes the social impacts of global warming.

Polar bears live in the Arctic , where they use the region’s ice floes as they hunt seals and other marine mammals . Temperature increases related to global warming have been the most pronounced at the poles, where they often make the difference between frozen and melted ice. Polar bears rely on small gaps in the ice to hunt their prey. As these gaps widen because of continued melting, prey capture has become more challenging for these animals.

Recent News

global warming , the phenomenon of increasing average air temperatures near the surface of Earth over the past one to two centuries. Climate scientists have since the mid-20th century gathered detailed observations of various weather phenomena (such as temperatures, precipitation , and storms) and of related influences on climate (such as ocean currents and the atmosphere’s chemical composition). These data indicate that Earth’s climate has changed over almost every conceivable timescale since the beginning of geologic time and that human activities since at least the beginning of the Industrial Revolution have a growing influence over the pace and extent of present-day climate change .

Giving voice to a growing conviction of most of the scientific community , the Intergovernmental Panel on Climate Change (IPCC) was formed in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Program (UNEP). The IPCC’s Sixth Assessment Report (AR6), published in 2021, noted that the best estimate of the increase in global average surface temperature between 1850 and 2019 was 1.07 °C (1.9 °F). An IPCC special report produced in 2018 noted that human beings and their activities have been responsible for a worldwide average temperature increase between 0.8 and 1.2 °C (1.4 and 2.2 °F) since preindustrial times, and most of the warming over the second half of the 20th century could be attributed to human activities.

AR6 produced a series of global climate predictions based on modeling five greenhouse gas emission scenarios that accounted for future emissions, mitigation (severity reduction) measures, and uncertainties in the model projections. Some of the main uncertainties include the precise role of feedback processes and the impacts of industrial pollutants known as aerosols , which may offset some warming. The lowest-emissions scenario, which assumed steep cuts in greenhouse gas emissions beginning in 2015, predicted that the global mean surface temperature would increase between 1.0 and 1.8 °C (1.8 and 3.2 °F) by 2100 relative to the 1850–1900 average. This range stood in stark contrast to the highest-emissions scenario, which predicted that the mean surface temperature would rise between 3.3 and 5.7 °C (5.9 and 10.2 °F) by 2100 based on the assumption that greenhouse gas emissions would continue to increase throughout the 21st century. The intermediate-emissions scenario, which assumed that emissions would stabilize by 2050 before declining gradually, projected an increase of between 2.1 and 3.5 °C (3.8 and 6.3 °F) by 2100.

Many climate scientists agree that significant societal, economic, and ecological damage would result if the global average temperature rose by more than 2 °C (3.6 °F) in such a short time. Such damage would include increased extinction of many plant and animal species, shifts in patterns of agriculture , and rising sea levels. By 2015 all but a few national governments had begun the process of instituting carbon reduction plans as part of the Paris Agreement , a treaty designed to help countries keep global warming to 1.5 °C (2.7 °F) above preindustrial levels in order to avoid the worst of the predicted effects. Whereas authors of the 2018 special report noted that should carbon emissions continue at their present rate, the increase in average near-surface air temperature would reach 1.5 °C sometime between 2030 and 2052, authors of the AR6 report suggested that this threshold would be reached by 2041 at the latest.

The AR6 report also noted that the global average sea level had risen by some 20 cm (7.9 inches) between 1901 and 2018 and that sea level rose faster in the second half of the 20th century than in the first half. It also predicted, again depending on a wide range of scenarios, that the global average sea level would rise by different amounts by 2100 relative to the 1995–2014 average. Under the report’s lowest-emission scenario, sea level would rise by 28–55 cm (11–21.7 inches), whereas, under the intermediate emissions scenario, sea level would rise by 44–76 cm (17.3–29.9 inches). The highest-emissions scenario suggested that sea level would rise by 63–101 cm (24.8–39.8 inches) by 2100.

The scenarios referred to above depend mainly on future concentrations of certain trace gases, called greenhouse gases , that have been injected into the lower atmosphere in increasing amounts through the burning of fossil fuels for industry, transportation , and residential uses. Modern global warming is the result of an increase in magnitude of the so-called greenhouse effect , a warming of Earth’s surface and lower atmosphere caused by the presence of water vapour , carbon dioxide , methane , nitrous oxides , and other greenhouse gases. In 2014 the IPCC first reported that concentrations of carbon dioxide, methane, and nitrous oxides in the atmosphere surpassed those found in ice cores dating back 800,000 years.

Of all these gases, carbon dioxide is the most important, both for its role in the greenhouse effect and for its role in the human economy. It has been estimated that, at the beginning of the industrial age in the mid-18th century, carbon dioxide concentrations in the atmosphere were roughly 280 parts per million (ppm). By the end of 2022 they had risen to 419 ppm, and, if fossil fuels continue to be burned at current rates, they are projected to reach 550 ppm by the mid-21st century—essentially, a doubling of carbon dioxide concentrations in 300 years.

A vigorous debate is in progress over the extent and seriousness of rising surface temperatures, the effects of past and future warming on human life, and the need for action to reduce future warming and deal with its consequences. This article provides an overview of the scientific background related to the subject of global warming. It considers the causes of rising near-surface air temperatures, the influencing factors, the process of climate research and forecasting, and the possible ecological and social impacts of rising temperatures. For an overview of the public policy developments related to global warming occurring since the mid-20th century, see global warming policy . For a detailed description of Earth’s climate, its processes, and the responses of living things to its changing nature, see climate . For additional background on how Earth’s climate has changed throughout geologic time , see climatic variation and change . For a full description of Earth’s gaseous envelope, within which climate change and global warming occur, see atmosphere .

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How did we get here the roots and impacts of the climate crisis.

People’s heavy reliance on fossil fuels and the cutting down of carbon-storing forests have transformed global climate.

For more than a century, researchers have honed their methods for measuring the impacts of human actions on Earth's atmosphere.

Sam Falconer

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By Alexandra Witze

March 10, 2022 at 11:00 am

Even in a world increasingly battered by weather extremes, the summer 2021 heat wave in the Pacific Northwest stood out. For several days in late June, cities such as Vancouver, Portland and Seattle baked in record temperatures that killed hundreds of people. On June 29, Lytton, a village in British Columbia, set an all-time heat record for Canada, at 121° Fahrenheit (49.6° Celsius); the next day, the village was incinerated by a wildfire.

Within a week, an international group of scientists had analyzed this extreme heat and concluded it would have been virtually impossible without climate change caused by humans. The planet’s average surface temperature has risen by at least 1.1 degrees Celsius since preindustrial levels of 1850–1900. The reason: People are loading the atmosphere with heat-trapping gases produced during the burning of fossil fuels, such as coal and gas, and from cutting down forests.

To celebrate our 100th anniversary, we’re highlighting some of the biggest advances in science over the last century. To see more from the series, visit Century of Science .

A little over 1 degree of warming may not sound like a lot. But it has already been enough to fundamentally transform how energy flows around the planet. The pace of change is accelerating, and the consequences are everywhere. Ice sheets in Greenland and Antarctica are melting, raising sea levels and flooding low-lying island nations and coastal cities. Drought is parching farmlands and the rivers that feed them. Wildfires are raging. Rains are becoming more intense, and weather patterns are shifting .

The roots of understanding this climate emergency trace back more than a century and a half. But it wasn’t until the 1950s that scientists began the detailed measurements of atmospheric carbon dioxide that would prove how much carbon is pouring from human activities. Beginning in the 1960s, researchers started developing comprehensive computer models that now illuminate the severity of the changes ahead.

Today we know that climate change and its consequences are real, and we are responsible. The emissions that people have been putting into the air for centuries — the emissions that made long-distance travel, economic growth and our material lives possible — have put us squarely on a warming trajectory . Only drastic cuts in carbon emissions, backed by collective global will, can make a significant difference.

“What’s happening to the planet is not routine,” says Ralph Keeling, a geochemist at the Scripps Institution of Oceanography in La Jolla, Calif. “We’re in a planetary crisis.”

Setting the stage

One day in the 1850s, Eunice Newton Foote, an amateur scientist and a women’s rights activist living in upstate New York, put two glass jars in sunlight. One contained regular air — a mix of nitrogen, oxygen and other gases including carbon dioxide — while the other contained just carbon dioxide. Both had thermometers in them. As the sun’s rays beat down, Foote observed that the jar of CO 2 alone heated up more quickly, and was slower to cool down, than the one containing plain air.

The results prompted Foote to muse on the relationship between CO 2 , the planet and heat. “An atmosphere of that gas would give to our earth a high temperature,” she wrote in an 1856 paper summarizing her findings .

Three years later, working independently and apparently unaware of Foote’s discovery, Irish physicist John Tyndall showed the same basic idea in more detail. With a set of pipes and devices to study the transmission of heat, he found that CO 2 gas, as well as water vapor, absorbed more heat than air alone. He argued that such gases would trap heat in Earth’s atmosphere, much as panes of glass trap heat in a greenhouse, and thus modulate climate.

Today Tyndall is widely credited with the discovery of how what we now call greenhouse gases heat the planet, earning him a prominent place in the history of climate science. Foote faded into relative obscurity — partly because of her gender, partly because her measurements were less sensitive. Yet their findings helped kick off broader scientific exploration of how the composition of gases in Earth’s atmosphere affects global temperatures.

Heat-trapping gases 

In 1859, John Tyndall used this apparatus to study how various gases trap heat. He sent infrared radiation through a tube filled with gas and measured the resulting temperature changes. Carbon dioxide and water vapor, he showed, absorb more heat than air does.

Carbon floods in

Humans began substantially affecting the atmosphere around the turn of the 19th century, when the Industrial Revolution took off in Britain. Factories burned tons of coal; fueled by fossil fuels, the steam engine revolutionized transportation and other industries. Since then, fossil fuels including oil and natural gas have been harnessed to drive a global economy. All these activities belch gases into the air.

Yet Swedish physical chemist Svante Arrhenius wasn’t worried about the Industrial Revolution when he began thinking in the late 1800s about changes in atmospheric CO 2 levels. He was instead curious about ice ages — including whether a decrease in volcanic eruptions, which can put carbon dioxide into the atmosphere, would lead to a future ice age. Bored and lonely in the wake of a divorce, Arrhenius set himself to months of laborious calculations involving moisture and heat transport in the atmosphere at different zones of latitude. In 1896, he reported that halving the amount of CO 2 in the atmosphere could indeed bring about an ice age — and that doubling CO 2 would raise global temperatures by around 5 to 6 degrees C.

It was a remarkably prescient finding for work that, out of necessity, had simplified Earth’s complex climate system down to just a few variables. But Arrhenius’ findings didn’t gain much traction with other scientists at the time. The climate system seemed too large, complex and inert to change in any meaningful way on a timescale that would be relevant to human society. Geologic evidence showed, for instance, that ice ages took thousands of years to start and end. What was there to worry about?

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One researcher, though, thought the idea was worth pursuing. Guy Stewart Callendar, a British engineer and amateur meteorologist, had tallied weather records over time, obsessively enough to determine that average temperatures were increasing at 147 weather stations around the globe. In a 1938 paper in a Royal Meteorological Society journal, he linked this temperature rise to the burning of fossil fuels . Callendar estimated that fossil fuel burning had put around 150 billion metric tons of CO 2 into the atmosphere since the late 19th century.

Like many of his day, Callendar didn’t see global warming as a problem. Extra CO 2 would surely stimulate plants to grow and allow crops to be farmed in new regions. “In any case the return of the deadly glaciers should be delayed indefinitely,” he wrote. But his work revived discussions tracing back to Tyndall and Arrhenius about how the planetary system responds to changing levels of gases in the atmosphere. And it began steering the conversation toward how human activities might drive those changes.

When World War II broke out the following year, the global conflict redrew the landscape for scientific research. Hugely important wartime technologies, such as radar and the atomic bomb, set the stage for “big science” studies that brought nations together to tackle high-stakes questions of global reach. And that allowed modern climate science to emerge.

The Keeling curve

One major effort was the International Geophysical Year, or IGY, an 18-month push in 1957–1958 that involved a wide array of scientific field campaigns including exploration in the Arctic and Antarctica. Climate change wasn’t a high research priority during the IGY, but some scientists in California, led by Roger Revelle of the Scripps Institution of Oceanography, used the funding influx to begin a project they’d long wanted to do. The goal was to measure CO 2 levels at different locations around the world, accurately and consistently.

The job fell to geochemist Charles David Keeling, who put ultraprecise CO 2 monitors in Antarctica and on the Hawaiian volcano of Mauna Loa. Funds soon ran out to maintain the Antarctic record, but the Mauna Loa measurements continued. Thus was born one of the most iconic datasets in all of science — the “Keeling curve,” which tracks the rise of atmospheric CO 2 .

When Keeling began his measurements in 1958, CO 2 made up 315 parts per million of the global atmosphere. Within just a few years it became clear that the number was increasing year by year. Because plants take up CO 2 as they grow in spring and summer and release it as they decompose in fall and winter, CO 2 concentrations rose and fell each year in a sawtooth pattern. But superimposed on that pattern was a steady march upward.

“The graph got flashed all over the place — it was just such a striking image,” says Ralph Keeling, who is Keeling’s son. Over the years, as the curve marched higher, “it had a really important role historically in waking people up to the problem of climate change.” The Keeling curve has been featured in countless earth science textbooks, congressional hearings and in Al Gore’s 2006 documentary on climate change, An Inconvenient Truth .

Each year the curve keeps going up: In 2016, it passed 400 ppm of CO 2 in the atmosphere as measured during its typical annual minimum in September. Today it is at 413 ppm. (Before the Industrial Revolution, CO 2 levels in the atmosphere had been stable for centuries at around 280 ppm.)

Around the time that Keeling’s measurements were kicking off, Revelle also helped develop an important argument that the CO 2 from human activities was building up in Earth’s atmosphere. In 1957, he and Hans Suess, also at Scripps at the time, published a paper that traced the flow of radioactive carbon through the oceans and the atmosphere . They showed that the oceans were not capable of taking up as much CO 2 as previously thought; the implication was that much of the gas must be going into the atmosphere instead.

Steady rise 

Known as the Keeling curve, this chart shows the rise in CO 2 levels as measured at the Mauna Loa Observatory in Hawaii due to human activities. The visible sawtooth pattern is due to seasonal plant growth: Plants take up CO 2   in the growing seasons, then release it as they decompose in fall and winter.

Monthly average CO 2 concentrations at Mauna Loa Observatory

“Human beings are now carrying out a large-scale geophysical experiment of a kind that could not have happened in the past nor be reproduced in the future,” Revelle and Suess wrote in the paper. It’s one of the most famous sentences in earth science history.

Here was the insight underlying modern climate science: Atmospheric carbon dioxide is increasing, and humans are causing the buildup. Revelle and Suess became the final piece in a puzzle dating back to Svante Arrhenius and John Tyndall. “I tell my students that to understand the basics of climate change, you need to have the cutting-edge science of the 1860s, the cutting-edge math of the 1890s and the cutting-edge chemistry of the 1950s,” says Joshua Howe, an environmental historian at Reed College in Portland, Ore.

Evidence piles up

Observational data collected throughout the second half of the 20th century helped researchers gradually build their understanding of how human activities were transforming the planet.

Ice cores pulled from ice sheets, such as that atop Greenland, offer some of the most telling insights for understanding past climate change. Each year, snow falls atop the ice and compresses into a fresh layer of ice representing climate conditions at the time it formed. The abundance of certain forms, or isotopes, of oxygen and hydrogen in the ice allows scientists to calculate the temperature at which it formed, and air bubbles trapped within the ice reveal how much carbon dioxide and other greenhouse gases were in the atmosphere at that time. So drilling down into an ice sheet is like reading the pages of a history book that go back in time the deeper you go.

Scientists began reading these pages in the early 1960s, using ice cores drilled at a U.S. military base in northwest Greenland . Contrary to expectations that past climates were stable, the cores hinted that abrupt climate shifts had happened over the last 100,000 years. By 1979, an international group of researchers was pulling another deep ice core from a second location in Greenland — and it, too, showed that abrupt climate change had occurred in the past. In the late 1980s and early 1990s, a pair of European- and U.S.-led drilling projects retrieved even deeper cores from near the top of the ice sheet, pushing the record of past temperatures back a quarter of a million years.

Together with other sources of information, such as sediment cores drilled from the seafloor and molecules preserved in ancient rocks, the ice cores allowed scientists to reconstruct past temperature changes in extraordinary detail. Many of those changes happened alarmingly fast. For instance, the climate in Greenland warmed abruptly more than 20 times in the last 80,000 years , with the changes occurring in a matter of decades. More recently, a cold spell that set in around 13,000 years ago suddenly came to an end around 11,500 years ago — and temperatures in Greenland rose 10 degrees C in a decade.

Evidence for such dramatic climate shifts laid to rest any lingering ideas that global climate change would be slow and unlikely to occur on a timescale that humans should worry about. “It’s an important reminder of how ‘tippy’ things can be,” says Jessica Tierney, a paleoclimatologist at the University of Arizona in Tucson.

More evidence of global change came from Earth-observing satellites, which brought a new planet-wide perspective on global warming beginning in the 1960s. From their viewpoint in the sky, satellites have measured the rise in global sea level — currently 3.4 millimeters per year and accelerating, as warming water expands and as ice sheets melt — as well as the rapid decline in ice left floating on the Arctic Ocean each summer at the end of the melt season. Gravity-sensing satellites have “weighed” the Antarctic and Greenlandic ice sheets from above since 2002, reporting that more than 400 billion metric tons of ice are lost each year.

Temperature observations taken at weather stations around the world also confirm that we are living in the hottest years on record. The 10 warmest years since record keeping began in 1880 have all occurred since 2005 . And nine of those 10 have come since 2010.

Worrisome predictions

By the 1960s, there was no denying that the planet was warming. But understanding the consequences of those changes — including the threat to human health and well-being — would require more than observational data. Looking to the future depended on computer simulations: complex calculations of how energy flows through the planetary system.

A first step in building such climate models was to connect everyday observations of weather to the concept of forecasting future climate. During World War I, British mathematician Lewis Fry Richardson imagined tens of thousands of meteorologists, each calculating conditions for a small part of the atmosphere but collectively piecing together a global forecast.

But it wasn’t until after World War II that computational power turned Richardson’s dream into reality. In the wake of the Allied victory, which relied on accurate weather forecasts for everything from planning D-Day to figuring out when and where to drop the atomic bombs, leading U.S. mathematicians acquired funding from the federal government to improve predictions. In 1950, a team led by Jule Charney, a meteorologist at the Institute for Advanced Study in Princeton, N.J., used the ENIAC, the first U.S. programmable, electronic computer, to produce the first computer-driven regional weather forecast . The forecasting was slow and rudimentary, but it built on Richardson’s ideas of dividing the atmosphere into squares, or cells, and computing the weather for each of those. The work set the stage for decades of climate modeling to follow.

By 1956, Norman Phillips, a member of Charney’s team, had produced the world’s first general circulation model, which captured how energy flows between the oceans, atmosphere and land. The field of climate modeling was born.

The work was basic at first because early computers simply didn’t have much computational power to simulate all aspects of the planetary system.

An important breakthrough came in 1967, when meteorologists Syukuro Manabe and Richard Wetherald — both at the Geophysical Fluid Dynamics Laboratory in Princeton, a lab born from Charney’s group — published a paper in the Journal of the Atmospheric Sciences that modeled connections between Earth’s surface and atmosphere and calculated how changes in CO 2 would affect the planet’s temperature. Manabe and Wetherald were the first to build a computer model that captured the relevant processes that drive climate , and to accurately simulate how the Earth responds to those processes.

The rise of climate modeling allowed scientists to more accurately envision the impacts of global warming. In 1979, Charney and other experts met in Woods Hole, Mass., to try to put together a scientific consensus on what increasing levels of CO 2 would mean for the planet. The resulting “Charney report” concluded that rising CO 2 in the atmosphere would lead to additional and significant climate change.

In the decades since, climate modeling has gotten increasingly sophisticated . And as climate science firmed up, climate change became a political issue.

The hockey stick 

This famous graph, produced by scientist Michael Mann and colleagues, and then reproduced in a 2001 report by the Intergovernmental Panel on Climate Change, dramatically captures temperature change over time. Climate change skeptics made it the center of an all-out attack on climate science.

The rising public awareness of climate change, and battles over what to do about it, emerged alongside awareness of other environmental issues in the 1960s and ’70s. Rachel Carson’s 1962 book Silent Spring , which condemned the pesticide DDT for its ecological impacts, catalyzed environmental activism in the United States and led to the first Earth Day in 1970.

In 1974, scientists discovered another major global environmental threat — the Antarctic ozone hole, which had some important parallels to and differences from the climate change story. Chemists Mario Molina and F. Sherwood Rowland, of the University of California, Irvine, reported that chlorofluorocarbon chemicals, used in products such as spray cans and refrigerants, caused a chain of reactions that gnawed away at the atmosphere’s protective ozone layer . The resulting ozone hole, which forms over Antarctica every spring, allows more ultraviolet radiation from the sun to make it through Earth’s atmosphere and reach the surface, where it can cause skin cancer and eye damage.

Governments worked under the auspices of the United Nations to craft the 1987 Montreal Protocol, which strictly limited the manufacture of chlorofluorocarbons . In the years following, the ozone hole began to heal. But fighting climate change is proving to be far more challenging. Transforming entire energy sectors to reduce or eliminate carbon emissions is much more difficult than replacing a set of industrial chemicals.

In 1980, though, researchers took an important step toward banding together to synthesize the scientific understanding of climate change and bring it to the attention of international policy makers. It started at a small scientific conference in Villach, Austria, on the seriousness of climate change. On the train ride home from the meeting, Swedish meteorologist Bert Bolin talked with other participants about how a broader, deeper and more international analysis was needed. In 1988, a United Nations body called the Intergovernmental Panel on Climate Change, the IPCC, was born. Bolin was its first chairperson.

The IPCC became a highly influential and unique body. It performs no original scientific research; instead, it synthesizes and summarizes the vast literature of climate science for policy makers to consider — primarily through massive reports issued every couple of years. The first IPCC report, in 1990 , predicted that the planet’s global mean temperature would rise more quickly in the following century than at any point in the last 10,000 years, due to increasing greenhouse gases in the atmosphere.

IPCC reports have played a key role in providing scientific information for nations discussing how to stabilize greenhouse gas concentrations. This process started with the Rio Earth Summit in 1992 , which resulted in the U.N. Framework Convention on Climate Change. Annual U.N. meetings to tackle climate change led to the first international commitments to reduce emissions, the Kyoto Protocol of 1997 . Under it, developed countries committed to reduce emissions of CO 2 and other greenhouse gases. By 2007, the IPCC declared the reality of climate warming is “unequivocal.” The group received the Nobel Peace Prize that year, along with Al Gore, for their work on climate change.

The IPCC process ensured that policy makers had the best science at hand when they came to the table to discuss cutting emissions. Of course, nations did not have to abide by that science — and they often didn’t. Throughout the 2000s and 2010s, international climate meetings discussed less hard-core science and more issues of equity. Countries such as China and India pointed out that they needed energy to develop their economies and that nations responsible for the bulk of emissions through history, such as the United States, needed to lead the way in cutting greenhouse gases.

Meanwhile, residents of some of the most vulnerable nations, such as low-lying islands that are threatened by sea level rise, gained visibility and clout at international negotiating forums. “The issues around equity have always been very uniquely challenging in this collective action problem,” says Rachel Cleetus, a climate policy expert with the Union of Concerned Scientists in Cambridge, Mass.

By 2015, the world’s nations had made some progress on the emissions cuts laid out in the Kyoto Protocol, but it was still not enough to achieve substantial global reductions. That year, a key U.N. climate conference in Paris produced an international agreement to try to limit global warming to 2 degrees C, and preferably 1.5 degrees C , above preindustrial levels.

Every country has its own approach to the challenge of addressing climate change. In the United States, which gets approximately 80 percent of its energy from fossil fuels, sophisticated efforts to downplay and critique the science led to major delays in climate action. For decades, U.S. fossil fuel companies such as ExxonMobil worked to influence politicians to take as little action on emissions reductions as possible.

Biggest footprint 

These 20 nations have emitted the largest cumulative amounts of carbon dioxide since 1850. Emissions are shown in billions of metric tons and are broken down into subtotals from fossil fuel use and cement manufacturing (blue) and land use and forestry (green).

Total carbon dioxide emissions by country, 1850–2021 

Such tactics undoubtedly succeeded in feeding politicians’ delay on climate action in the United States, most of it from Republicans. President George W. Bush withdrew the country from the Kyoto Protocol in 2001 ; Donald Trump similarly rejected the Paris accord in 2017 . As late as 2015, the chair of the Senate’s environment committee, James Inhofe of Oklahoma, brought a snowball into Congress on a cold winter’s day to argue that human-caused global warming is a “hoax.”

In Australia, a similar mix of right-wing denialism and fossil fuel interests has kept climate change commitments in flux, as prime ministers are voted in and out over fierce debates about how the nation should act on climate.

Yet other nations have moved forward. Some European countries such as Germany aggressively pursued renewable energies, including wind and solar, while activists such as Swedish teenager Greta Thunberg — the vanguard of a youth-action movement — pressured their governments for more.

In recent years, the developing economies of China and India have taken center stage in discussions about climate action. China, which is now the world’s largest carbon emitter, declared several moderate steps in 2021 to reduce emissions, including that it would stop building coal-burning power plants overseas. India announced it would aim for net-zero emissions by 2070, the first time it has set a date for this goal.

Yet such pledges continue to be criticized. At the 2021 U.N. Climate Change Conference in Glasgow, Scotland, India was globally criticized for not committing to a complete phaseout of coal — although the two top emitters, China and the United States, have not themselves committed to phasing out coal. “There is no equity in this,” says Aayushi Awasthy, an energy economist at the University of East Anglia in England.

Past and future 

Various scenarios for how greenhouse gas emissions might change going forward help scientists predict future climate change. This graph shows the simulated historical temperature trend along with future projections of rising temperatures based on five scenarios from the Intergovernmental Panel on Climate Change. Temperature change is the difference from the 1850–1900 average.

Historical and projected global temperature change

Facing the future

In many cases, changes are coming faster than scientists had envisioned a few decades ago. The oceans are becoming more acidic as they absorb CO 2 , harming tiny marine organisms that build protective calcium carbonate shells and are the base of the marine food web. Warmer waters are bleaching coral reefs. Higher temperatures are driving animal and plant species into areas in which they previously did not live, increasing the risk of extinction for many.

No place on the planet is unaffected. In many areas, higher temperatures have led to major droughts, which dry out vegetation and provide additional fuel for wildfires such as those that have devastated Australia , the Mediterranean and western North America in recent years.

Then there’s the Arctic, where temperatures are rising at more than twice the global average and communities are at the forefront of change. Permafrost is thawing, destabilizing buildings, pipelines and roads. Caribou and reindeer herders worry about the increased risk of parasites for the health of their animals. With less sea ice available to buffer the coast from storm erosion, the Inupiat village of Shishmaref, Alaska, risks crumbling into the sea . It will need to move from its sand-barrier island to the mainland.

“We know these changes are happening and that the Titanic is sinking,” says Louise Farquharson, a geomorphologist at the University of Alaska Fairbanks who monitors permafrost and coastal change around Alaska. All around the planet, those who depend on intact ecosystems for their survival face the greatest threat from climate change. And those with the least resources to adapt to climate change are the ones who feel it first.

“We are going to warm,” says Claudia Tebaldi, a climate scientist at Lawrence Berkeley National Laboratory in California. “There is no question about it. The only thing that we can hope to do is to warm a little more slowly.”

That’s one reason why the IPCC report released in 2021 focuses on anticipated levels of global warming . There is a big difference between the planet warming 1.5 degrees versus 2 degrees or 2.5 degrees. Each fraction of a degree of warming increases the risk of extreme events such as heat waves and heavy rains, leading to greater global devastation.

The future rests on how much nations are willing to commit to cutting emissions and whether they will stick to those commitments. It’s a geopolitical balancing act the likes of which the world has never seen.

Science can and must play a role going forward. Improved climate models will illuminate what changes are expected at the regional scale, helping officials prepare. Governments and industry have crucial parts to play as well. They can invest in technologies, such as carbon sequestration, to help decarbonize the economy and shift society toward more renewable sources of energy.

Huge questions remain. Do voters have the will to demand significant energy transitions from their governments? How can business and military leaders play a bigger role in driving climate action? What should be the role of low-carbon energy sources that come with downsides, such as nuclear energy? How can developing nations achieve a better standard of living for their people while not becoming big greenhouse gas emitters? How can we keep the most vulnerable from being disproportionately harmed during extreme events, and incorporate environmental and social justice into our future?

These questions become more pressing each year, as carbon dioxideaccumulates in our atmosphere. The planet is now at higher levels of CO 2 than at any time in the last 3 million years.

At the U.N. climate meeting in Glasgow in 2021, diplomats from around the world agreed to work more urgently to shift away from using fossil fuels. They did not, however, adopt targets strict enough to keep the world below a warming of 1.5 degrees.

It’s been well over a century since chemist Svante Arrhenius recognized the consequences of putting extra carbon dioxide into the atmosphere. Yet the world has not pulled together to avoid the most dangerous consequences of climate change.

Time is running out.

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Facts and opinions about climate change

By Richard C. J. Somerville | December 7, 2020

Editor’s note: This article is adapted from a public lecture for the Aquarium of the Pacific in Long Beach, Calif. [1]

When the Bulletin of the Atomic Scientists was founded, climate change science was in its infancy. There were no global climate models, no supercomputers, and no satellite remote-sensing data. Only a few visionaries understood that man-made increases in the amount of carbon dioxide (CO 2 ) might cause large global climate changes. The definitive summary of atmospheric science in the decade after World War II was the Compendium of Meteorology , a large multi-authored volume published in 1951 by the American Meteorological Society. Its article on climate change, written by the distinguished British climatologist C. E. P. Brooks, reflects the prevailing expert opinion of that time.

The article began with this statement:

“In the past hundred years the burning of coal has increased the amount of CO 2 by a measurable amount (from 0.028 to 0.030 per cent), and Callendar (1939) sees in this an explanation of the recent rise in world temperature. But during the past 7,000 years there have been greater fluctuations of temperature without the intervention of man, and there seems to be no reason to regard the recent rise as more than a coincidence. This theory is not considered further.”

It is important to distinguish between facts and opinions. “Everyone is entitled to his own opinion, but not to his own facts.” Daniel Patrick Moynihan , who said that, was a wise and accomplished American politician, sociologist, and diplomat. Like everybody, I know some facts, and I have some opinions. I will first summarize the facts that we have learned from the science of climate change. Then I will give some opinions about what people and governments should do.

I think any rational response to climate change involves first knowing what the facts and evidence are. That is the province of science. There are many indicators measured globally over many decades that show that the Earth’s climate is warming. All the indicators expected to increase in a warming world are increasing, and all those expected to decrease in a warming world are decreasing. It’s definitely warming. It’s not a hoax. We observe it and measure it. The atmosphere is warming. So is the ocean. Sea level is rising. Ice sheets and glaciers and snow cover are shrinking. The amount of water vapor in the atmosphere is increasing. Climate change is real and serious. It’s not a remote threat for the distant future. It’s here and now.

It’s us. We’ve done the detective work. Just as wildfire experts can say whether a fire was caused by lightning, or by a campfire accidentally left burning, or by arson, we can show what is now causing the world to warm. Yes, some past climate change was natural, like ice ages coming and going, but the warming we have observed in recent decades is clearly caused by human activities. The evidence for that is overwhelming.

We now know what paces the beginnings and ends of ice ages. It is slow changes in the Earth’s orbit around the sun, that alter how sunlight is distributed over the surface of the Earth. We understand these changes in the orbit, and they take thousands of years to have an effect. They cannot possibly produce the climate changes that we observe occurring in just a few decades. Similarly, we can rule out other natural processes, such as changes in the energy in sunlight. They are quantitatively too small. Human activities, such as burning coal and oil and natural gas, are the dominant cause of the rapid climate change we now observe.

It hasn’t stopped. The warming is still continuing. We have good estimates of the global average temperature of the Earth’s surface from 1880 until the present; 1880 is about the time when we first had enough good thermometers located in enough places around the Earth to enable us to calculate a meaningful global average. The modern data is the most accurate. During about the last 50 years, from the 1970s until now, we know there has been a warming of about 1 degree Celsius, or 1.8 degrees Fahrenheit. All the warmest years on record are recent years.

The heat is mainly in the sea. Over 90 percent of the heat added to the climate system is in the oceans. How do we measure the heat stored in the ocean? That’s a good question, and it has a fascinating answer.

We now measure this increase in ocean heat content from an array of about 4,000 autonomous floats deployed throughout the world ocean under an international program called Argo . They have no engines and no propellers, but they move with the ocean currents at a depth of 1,000 meters, which is about 10 football fields. That’s where they are usually parked, and they are programmed to periodically sink another 1,000 meters lower and then rise to the surface while measuring quantities such as water temperature and salinity. They rise and sink by changing their volume. This is accomplished by pumping fluid into or out of a bladder on the float.

The floats store the measurements, and then, when they are on the surface, they locate by GPS and transmit the stored data via satellites to scientists. The change in float locations between one transmission and the next provides information on the currents at the depth where the floats were parked. As their batteries fail, the floats end their useful lives and must be replaced by new floats. The Argo floats have revolutionized our ability to observe the oceans. Argo data are available to everyone for free in near real time. New floats, allowing sampling to much greater depths, are now being developed.

Sea level is rising globally. We measure it from altimeters on satellites. There has been a rise of about 100 millimeters, which is about 4 inches, over the last 30 years or so. The rate of sea level rise is increasing too. Future sea level rise will be much greater than past sea level rise. The sea level rise is different at different locations on the Earth. Local sea level is affected by whether the land at that location is rising or sinking, and also by ocean currents, tides and other factors.

Ice is shrinking. Ice sheets on Greenland and Antarctica and almost every glacier worldwide are all shrinking. We know this from satellite missions called GRACE (the Gravity Recovery and Climate Experiment ). These satellites determine the mass of the ice accurately by measuring the effect of the ice sheet on the Earth’s gravity. The technology of the GRACE missions involves two satellites in the same orbit which have a means of measuring the distance between the two satellites extremely accurately. This distance changes when gravity varies, which occurs when passing over ice sheets, and measuring the tiny change in the inter-satellite distance allows scientists to determine the mass of the ice.

Carbon dioxide absorbed by the ocean makes it more nearly acidic. That can affect the marine ecosystem and the food chain. The ocean absorbs some of the CO 2 that we emit into the atmosphere. Measurements show that the acidity parameter called pH is decreasing. Seawater is slightly basic (its pH is greater than 7), and we observe a shift towards neutral conditions (pH = 7), rather than to truly acidic conditions (pH less than 7).

Carbon dioxide amounts in the atmosphere, because of human activities, are now about 45 percent higher than they were in the early 1800s. We have good measurements of atmospheric CO 2 amounts over the last 800,000 years. These data come from analyzing fossil air trapped in ice in Greenland and Antarctica. They reveal large variations in CO 2 amounts, associated with ice ages starting and ending. Orbital variations pace the ice ages, causing the CO 2 amounts to change, and initiating a feedback that increases the magnitude of the temperature change.

The amount of carbon dioxide in the atmosphere now is the highest it has been in millions of years. The atmospheric CO 2 amounts in the even more distant geological past, many million years ago, sometimes have been even higher than at present, but the world was a very different place then, which was long before any human beings existed.

Cumulative emissions of carbon dioxide set the amount of warming. The warming caused by CO 2 in recent decades is, to a good approximation, just linearly proportional to the total cumulative amount of carbon emitted into the atmosphere. We do not know exactly how much added CO2 will produce how much warming—that is, the climate sensitivity question—but we can estimate a range of possible answers to this question, constrained by different kinds of observations. For the middle of the range, 1 trillion metric tons of carbon emitted produces a warming of about 2 degrees Celsius above the temperatures of the early 1800s. We have already emitted about half of this amount. At present, the warming we observe is caused by CO 2 plus several other heat-trapping substances that human activities have also added to the atmosphere. The amounts in the atmosphere of these other substances will decrease rapidly when and if their sources are eliminated, but some of the carbon dioxide will remain in the atmosphere for thousands of years. Because of the difference in the amount of time that different heat-trapping substances stay in the atmosphere, carbon dioxide is truly the key “control knob” for climate.

Reducing emissions of carbon dioxide and other heat-trapping substances will limit the warming. We can estimate the cumulative amount of carbon emitted that would give us a good chance of limiting warming to 2 degrees Celsius (that’s 3.6 degrees Fahrenheit) above the pre-industrial temperatures of the early 1800s. This is the warming target endorsed by the Paris Agreement of 2015. If emissions had peaked and began to decline several decades ago, then emissions reductions could be gradual, and by 2050 emissions would not yet need to have entirely stopped. Because emissions are still increasing, drastic emissions reductions need to occur quickly and reach zero by 2040.

“Negative emissions,” meaning removing some carbon dioxide from the air, are likely to be necessary. This fact illustrates the urgency of acting. Finding a way of removing some of the carbon dioxide is one approach to geoengineering. Here by “geoengineering” we mean the intentional modification of the climate system with the goal of reducing or mitigating climate change. However, nobody has yet demonstrated a way of economically removing large amounts of carbon dioxide from the atmosphere.

The longer we wait before acting, the more drastic the action has to be. The result of failing to act is to increase the likelihood of dangerous climate change.

Because it takes so long for the carbon dioxide in the atmosphere to decrease, climate change will last for centuries. After emissions completely stop, the amount of carbon dioxide in the atmosphere decreases only slowly for several centuries, and about 25 percent of it remains in the atmosphere for the next 10,000 years or so. The science relevant to this topic is not simple. Several complex processes for carbon removal are involved. The key take-away message is that the climate change caused by adding carbon dioxide to the atmosphere can have very long-lasting effects.

The conclusions I have just recounted are facts. They are fundamental findings from extensive scientific research. They are all well-supported by abundant evidence.

The science is never complete. There is always more to learn. But the science that we have now is already good enough to help us make wise decisions. The many unknowns in the science, such as exactly how fast the Antarctic ice sheet will shrink or exactly how El Niño might be affected, are not the biggest unknowns about future climate. The biggest unknown about future climate is human behavior. Everything depends on what people and their governments do.

The scientific consensus is overwhelming. Climate change is already happening, here and now. About 97 percent of climate experts—the scientists who are most active in carrying out and publishing research on climate change—agree that the observed recent warming is real and serious and overwhelmingly human-caused, and that it will become even more serious unless we make big changes in how we generate energy. Nevertheless, some people remain unconvinced. They continue to repeat climate myths and falsehoods.

People often ask me, “I’m only one person. What can I do about climate change?” Here is my answer. We need to persuade more people that this problem is serious. Governments tend to respond when enough people become concerned, and when they vote their concerns. I urge everyone to engage with people you may know—family, friends, colleagues—who don’t accept the fundamental findings of climate science. Explain to them the facts you have learned about our changing climate. Listen to them respectfully and carefully. Be alert to the common climate myths and falsehoods that they may think are true. If you see something, say something. Have a civil conversation. Have many conversations. In their hearts, almost all of us would surely agree that everybody is entitled to his own opinions, but not to his own facts. And it is science that supplies the facts about climate change.

We humans have become the dominant actors in causing the rapid climate change we now observe. Human actions now overwhelm all the natural processes. This may seem counter-intuitive, but it’s true. You and I, and all the people who are alive today, now have our hands on the thermostat that controls the climate of our children and grandchildren. Metaphors can be superb communication tools. The thermostat is a powerful metaphor.

Think about medical metaphors. Here are a few: We climate scientists are planetary physicians. Climate science and medical science will both always be imperfect and incomplete, but both are already very useful.

When your doctor tells you to stop smoking and lose weight and exercise more, you don’t argue with her. You don’t call her a radical alarmist. You don’t ask her to name the date when you will have a heart attack.

Physicians have advanced academic credentials and many years of training and experience. We climate scientists have the same. We’re not conspiring to fool people. Do you really think your doctor is a crook? She’s not. Neither are we.

A fever of only a few degrees can indicate a serious disease. Global warming is just a symptom of planetary ill health, like a fever.

Prevention is better than cure. Quitting smoking, like quitting using fossil fuels, is not easy to do. And the main benefits of quitting come in the long-term future.

Choosing to have major surgery involves cost and risk. People know that choosing to do nothing also has costs and risks.

The laws of climate science and medical science are all immune from political tampering. You can’t fool Mother Nature. Mother Nature always bats last.

Here’s an effective metaphor. Imagine you are watching a major-league baseball game. The slugger who is thought to be on performance-enhancing drugs hits a home run. The person next to you asks, did the steroids cause it? That’s really the wrong question. You can’t be sure they caused it, because he was already a big-league slugger when he was clean. And even with the drugs, he can still strike out now and then. But at the end of the season, you see in his statistics that he hit more homers than he used to. The steroids increase the odds of home runs. Climate is the statistics of weather, and carbon dioxide is the steroids of climate. [2] It changes the odds. The odds are higher now for all sorts of extreme weather, because climate change has altered the environment in which all weather occurs.

This metaphor works for other sports too. For example, baseball isn’t popular in France, but bicycle racing is very popular there, and French people know that a bike racer on drugs won’t win every race, but the drugs do change the odds and increase his probability of winning.

The main barriers to action on climate change are a lack of widespread political will and a lack of wise and inspiring leadership. Science can help to inform policy, but only concerned people and responsive, capable governments can first decide what policies are best, and then implement them. Today, despite a strong scientific consensus, climate change is controversial politically.

We do not have to accept a future with devastating climate damage and disruption. If we continue to use more and more fossil fuels to generate the world’s energy, we will be sentencing our children and grandchildren to many centuries with a severely damaged climate and great suffering. In your conversations, try to help people understand that this bleak future is entirely preventable.

Faced with these threats, almost all the nations of the world agreed in Paris in late 2015 to limit the warming to a specific maximum amount. That amount is 2 degrees Celsius, or 3.6 degrees Fahrenheit, above the average global temperature in the early 1800s, before human activities began to have a large effect

After Paris, is the glass half-empty or half-full? I am guardedly optimistic, for these reasons:

• World leaders are now engaged; at least almost all of them are.
• Emissions of heat-trapping gases have begun to decline in some places.
• Solar and wind energy are getting cheaper every year.
• Renewable energy use is increasing rapidly.
• Many corporations are now acting to reduce emissions.
• State and local governments in the United States are acting too, despite federal inaction.
• Many other countries are showing rapid progress.

Recent polling shows that in the United States, many more people accept the science and are very concerned about global warming or climate change than was the case only a few years ago. However, the issue has become extremely partisan. Recent polls show that the substantial increase in the number of Americans calling climate change a top priority has been limited to the Democratic side of the political spectrum. However, about 80 percent of Republicans, including virtually the entire leadership of the Republican party, have not changed their minds and still reject the science. We have a long way to go. I think we should keep climate change science separated from climate change policy.

There is no silver bullet that solves all the challenges of climate change, but there is a lot of silver buckshot, including increased energy efficiency and energy conservation, and much more use of sun, wind and water to provide the energy the world needs. These renewable resources are widely available now and already cost-competitive with fossil fuels. We have the technology, and it is improving. In the United States, even without energetic action by the federal government, I am guardedly optimistic.

Market forces now favor carbon-free energy. Coal companies are going bankrupt. Solar and wind energy without subsidies are in many cases already cheaper than fossil fuels. Electric vehicles are happening fast. Much energy policy in the US is set at state and local levels, not in Washington.

Always remember why we want to have conversations about climate change science. We want to inform people. We want to motivate them. We want them to act.

Research suggests that messages that may invoke fear or dismay are better received if they also include hope. We should include positive messages about our ability to solve the problem. We can explain that future climate is in our hands.

Politics and priorities and values do have a role to play in deciding which actions are best, but any rational policy begins by accepting the science. People are entitled to their own opinions, but not to their own facts.

This article is being written in 2020 during the global coronavirus pandemic, and I have a few gentle words to say about some climate change lessons that we might learn from the pandemic now gripping the entire world.

One obvious point is that climate change science, like coronavirus epidemiology, is incomplete, still developing but already extremely useful. In both domains, we have learned we can trust scientists more than politicians or pundits or anybody else who is not really an expert on the science of the subject, whether the subject is climate change or infectious diseases. We have also learned that the challenges in both climate change and the pandemic are global. The entire world is affected. The solutions have to be global too.

The pandemic also illustrates the wisdom of the statement that, “Everybody is entitled to his own opinions, but not to his own facts.” The facts about climate change, and about COVID-19, are objective truth, and they should be the same for everybody, regardless of people’s ideology or politics. When it comes to making policy, sound science can inform wise policy. However, policy can also depend on many other factors, such as people’s priorities, their convictions about economics, what they regard as the proper role of governments, their risk tolerance, and, of course, public opinion. That’s true for meeting the challenge of climate change, just as for meeting the challenge of COVID-19.

The pandemic reminds us how valuable science and scientists are. The recent discussions in the news—such as about how clinical trials of drugs and vaccines work—are very educational. The medical scientists who develop new medicines do their best to make sure they are safe and effective, and they won’t release them for widespread use to the public until they are absolutely convinced of that. They are real experts and are very careful.

So are climate scientists.

Tony Fauci, who has often been on television recently in the United States, is a good example of a person who is a real expert on pandemics. He says simply, “I’m a physician and a scientist.” People get that. When Fauci speaks to the public, he is not trying to be popular or make people happy or brag about himself or make money. He is just telling people the facts that scientists have discovered, and he describes these facts in a way that is honest and transparent and understandable. He has spent his entire career accumulating expertise and experience and wisdom about infectious diseases and pandemics. People should trust him, and polls show that the great majority of people do trust him. Science is absolutely essential. That’s true for pandemics.

It’s also true for climate change.

Like many interested people, I watched Warren Buffett’s 2020 Berkshire Hathaway stockholders meeting online. Warren Buffett, the brilliant investor and one of the richest people in the world, agrees with me. Here’s what he said:

“I think, personally I feel extraordinarily good about being able to listen to Dr. Fauci, who I had never heard of a year ago. But I think we’re very, very fortunate as a country to have somebody at 79 years of age who appears to be able to work 24 hours a day and keep a good humor about him and communicate in a very, very straightforward matter about fairly complex subjects and tell you when he knows something and when he doesn’t know something. So, I’m not going to talk about any political figures at all or our politics generally this afternoon, but I do feel that I owe a huge debt of gratitude to Dr. Fauci for educating and informing me, actually along with my friend Bill Gates, too, as to what’s going on. I know I get it from a straight shooter when I get it from either one of those. So, thank you Dr. Fauci.”

[1] See https://youtu.be/DmUWPn6GCEg

[2] See https://youtu.be/MW3b8jSX7ec

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Keywords: Aquarium of the Pacific , GRACE , Gravity Recovery and Climate Experiment , climate change facts , climate change metaphors Topics: Climate Change , Multimedia

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I have difficulty putting much stock in the opinion of a scientist who only points to CO2 emissions from fossil fuels as the cause of climate change and fails to mention deforestation and shrinking of mangroves around the world.

Richard C. J. Somerville

Richard C. J. Somerville is an internationally recognized climate scientist. He has been a professor at the Scripps Institution of Oceanography at... Read More

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Climate Explained: Introductory Essays About Climate Change Topics

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Climate Explained, a part of Yale Climate Connections, is an essay collection that addresses an array of climate change questions and topics, including why it’s cold outside if global warming is real, how we know that humans are responsible for global warming, and the relationship between climate change and national security.

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Scientists Agree: Global Warming is Happening and Humans are the Primary Cause

Published Aug 3, 2017 Updated Jan 9, 2018

The evidence is overwhelming. Record-breaking temperatures, humidity, and sea level rise, along with many other indicators, show that the Earth is warming fast, and that all the heat-trapping emissions we release into the atmosphere from burning fossil fuels is changing our climate.

The Climate Accountability Scorecard

The time to act is now. But action isn't easy: many powerful industry interests have hindered climate solutions and spread dangerous myths about climate change.

One of the preferred tactics these groups use to sow confusion is to promote studies that either ignore or misrepresent the evidence of thousands of articles published in well-established and well-respected scientific journals, which show that global warming is happening and that it is caused by humans.

No matter how much contrarians try to cloak reality, the evidence is not going away.

Widespread scientific consensus

Scientists worldwide agree that global warming is happening, and that human activity causes it.

The IPCC Fifth Assessment Report ( AR5 ), written by a panel of hundreds of climate experts and scientists from member countries of the World Meteorological Organization the United Nations Environmental Programme , plus a team of external reviewers, states unambiguously:

Human influence on the climate system is clear, and recent anthropogenic emissions of green-house gases are the highest in history. […] Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. IPCC Fifth Assessment Report (AR5)

Building on two previous studies, a landmark 2013 peer-reviewed study evaluated 10,306 scientists to confirm that over 97 percent climate scientists agree, and over 97 percent of scientific articles find that global warming is real and largely caused by humans.

A 2016 peer-reviewed paper examined existing studies on consensus in climate research, and concluded that the 97 percent estimate is robust.

This level of consensus is equivalent to the level of agreement among scientists that smoking causes cancer – a statement that very few people, if any, contest today.

The US public also increasingly agrees that global warming is happening. A 2016 poll from Yale found that 70 percent of US residents believe global warming is happening, while record low numbers of people (12 percent) say the opposite.

A Gallup poll from 2017 showed that the number of people who worry “a great deal” about global warming has increased from 37 percent in 2016 to 45 percent in 2017.  The acceptance of human-caused emissions as the cause of warming is not keeping pace with those that believe it is happening, but it is at 53 percent.

There is no shortage of published research on the consensus of climate scientists and climate science when it comes to human-caused global warming. In addition to the references above, you can read about how the discussion on consensus developed over time in these studies .

Many different scientific societies in the United States and numerous national academies of science from around the world have also issued statements that verify the scientific claims about human-caused warming (see below).

Consensus and scientific uncertainty

Climate skeptics and deniers often misrepresent and aggrandize “ scientific uncertainty ” to undermine climate science consensus. When it comes to scientific consensus on global warming, it is important to clarify what type of uncertainty exists, and what type does not: there is strong certainty on the types of impacts that global warming is causing (or would be likely to cause under a given scenario for emissions), but less certainty on the exact timing and intensity of these impacts.  

When Rising Seas Hit Home

For instance, on the issue of sea level rise, we know with certainty that it will happen – it is already happening – and projections under different scenarios give us a range of possible rise.  We don’t know an exact value, however, for future sea level rise, because in large part it is dependent on the rate of future emissions, which is unknown.  

If emissions continue in a “business as usual” fashion, the sea level rise will be closer to the higher range of projections. But if we significantly reduce emissions, the rise will be closer to the lower levels of projections.

The same is true for how much warming will actually happen, or how much land-based ice and glaciers will melt. All these things are already happening, but future rates are not known because they, too, depend on the rate of future emissions. What scientists can calculate quite confidently is a narrow range of outcomes within a given scenario—meaning the likely highest and lowest values  if we continue on a certain path of emissions. This information is critical to making smart collective choices and for planning for the future.

Uncertainties are not a reason to delay action on climate change. Quite the contrary: those uncertainties are really a consequence of our collective choices, and a risk we must prepare for.

You can think about it like car insurance: everyone hopes they won’t be in a car accident but have accident insurance anyway, even though the likelihood is very low.

Climate adaptation and climate risk reduction are “insurance” against the effects of climate change, which in contrast are NOT low-probability events, but highly likely and predicted with high levels of certainty under specific conditions.  Being prepared for these scenarios is simply smart planning. Nobody wants to be caught unaware and unprepared.

Killer Heat in the United States

Consensus worldwide.

Many scientific societies and academies have released statements and studies that highlight the overwhelming consensus on climate change science.

American Association for the Advancement of Science: AAAS Reaffirms the Reality of Human-Caused Climate Change “Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research concludes that the greenhouse gases emitted by human activities are the primary driver. This conclusion is based on multiple independent lines of evidence and the vast body of peer-reviewed science.” (June 2016)

American Chemical Society : Statement on Global Climate Change “The Earth’s climate is changing in response to increasing concentrations of greenhouse gases (GHGs) and particulate matter in the atmosphere, largely as the result of human activities. … Unmitigated climate change will lead to increases in extreme weather events and will cause significant sea level rise, causing property damage and population displacement. It also will continue to degrade ecosystems and natural resources, affecting food and water availability and human health, further burdening economies and societies. Continued uncontrolled GHG emissions will accelerate and compound the effects and risks of climate change well into the future.” (2016)

American Geophysical Union : Human-induced Climate Change Requires Urgent Action.

"Extensive, independent observations confirm the reality of global warming. These observations show large-scale increases in air and sea temperatures, sea level, and atmospheric water vapor; they document decreases in the extent of mountain glaciers, snow cover, permafrost, and Arctic sea ice. These changes are broadly consistent with long-understood physics and predictions of how the climate system is expected to respond to human-caused increases in greenhouse gases. The changes are inconsistent with explanations of climate change that rely on known natural influences.”(December 2003, revised and reaffirmed December 2007, February 2012, August 2013)

American Meteorological Society: Climate Change: An Information Statement of the American Meteorological Society "It is clear from extensive scientific evidence that the dominant cause of the rapid change in climate of the past half century is human-induced increases in the amount of atmospheric greenhouse gases, including carbon dioxide (CO2), chlorofluorocarbons, methane, and nitrous oxide.” (August 2012)

American Physical Society : Statement on Earth’s Changing Climate

"While natural sources of climate variability are significant, multiple lines of evidence indicate that human influences have had an increasingly dominant effect on global climate warming observed since the mid-twentieth century. Although the magnitudes of future effects are uncertain, human influences on the climate are growing." (November 2015)

Geological Society of America : Position Statement on Climate Change "Scientific advances have greatly reduced previous uncertainties about recent global warming. Ground-station measurements have shown a warming trend of ~0.85 °C since 1880, a trend consistent with (1) retreat of northern hemisphere snow and Arctic sea ice; (2) greater heat storage in the ocean; (3) retreat of most mountain glaciers; (4) an ongoing rise in global sea level; and (5) proxy reconstructions of temperature change over past centuries from archives that include ice cores, tree rings, lake sediments, boreholes, cave deposits, and corals." (October 2006; revised April 2010, March 2013, April 2015).

Intergovernmental Panel on Climate Change: Synthesis Report Summary for Policymakers

“Human influence on the climate system is clear, and recent anthropogenic emissions of green-house gases are the highest in history. Recent climate changes have had widespread impacts on human and natural systems. “Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, and sea level has risen.” (2014)

International academies joint statement: Global response to climate change

“The world’s climate is changing, and the impacts are already being observed. Changing agricultural conditions, ocean warming and acidification, rising sea levels, and increased frequency and intensity of many extreme weather events are impacting infrastructure, environmental assets and human health.” (2018, African Academy of Sciences and the national academies of science of the United Kingdom, Australia, Bangladesh, Botswana, Canada, India, Mauritius, Mozambique, Nigeria, Pakistan, New Zealand, Cyprus, Singapore, Sri Lanka, South Africa, Scotland, Zimbabwe, Kenya, Zambia, Malaysia, Cameroon). 

US Global Change Research Program:  Highlights of the Findings of the U.S. Global Change Research Program Climate Science Special Report

“Based on extensive evidence, … it is extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century. For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence.

“In addition to warming, many other aspects of global climate are changing, primarily in response to human activities. Thousands of studies conducted by researchers around the world have documented changes in surface, atmospheric, and oceanic temperatures; melting glaciers; diminishing snow cover; shrinking sea ice; rising sea levels; ocean acidification; and increasing atmospheric water vapor.” (November 2017)

U.S. National Academy of Sciences : Understanding and Responding to Climate Change "The scientific understanding of climate change is now sufficiently clear to begin taking steps to prepare for climate change and to slow it." (2008)

Related resources

Water, Water Every Where

Looming Deadlines for Coastal Resilience

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The Science and Climate Litigation Webinar Series

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Essay on Global Warming

• Updated on  
• Apr 27, 2024

Being able to write an essay is an integral part of mastering any language. Essays form an integral part of many academic and scholastic exams like the SAT, and UPSC amongst many others. It is a crucial evaluative part of English proficiency tests as well like IELTS, TOEFL, etc. Major essays are meant to emphasize public issues of concern that can have significant consequences on the world. To understand the concept of Global Warming and its causes and effects, we must first examine the many factors that influence the planet’s temperature and what this implies for the world’s future. Here’s an unbiased look at the essay on Global Warming and other essential related topics.

Short Essay on Global Warming and Climate Change?

Since the industrial and scientific revolutions, Earth’s resources have been gradually depleted. Furthermore, the start of the world’s population’s exponential expansion is particularly hard on the environment. Simply put, as the population’s need for consumption grows, so does the use of natural resources , as well as the waste generated by that consumption.

Climate change has been one of the most significant long-term consequences of this. Climate change is more than just the rise or fall of global temperatures; it also affects rain cycles, wind patterns, cyclone frequencies, sea levels, and other factors. It has an impact on all major life groupings on the planet.

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What is Global Warming?

Global warming is the unusually rapid increase in Earth’s average surface temperature over the past century, primarily due to the greenhouse gases released by people burning fossil fuels . The greenhouse gases consist of methane, nitrous oxide, ozone, carbon dioxide, water vapour, and chlorofluorocarbons. The weather prediction has been becoming more complex with every passing year, with seasons more indistinguishable, and the general temperatures hotter.

The number of hurricanes, cyclones, droughts, floods, etc., has risen steadily since the onset of the 21st century. The supervillain behind all these changes is Global Warming. The name is quite self-explanatory; it means the rise in the temperature of the Earth.

Also Read: What is a Natural Disaster?

What are the Causes of Global Warming?

According to recent studies, many scientists believe the following are the primary four causes of global warming:

• Deforestation 
• Greenhouse emissions
• Carbon emissions per capita

Extreme global warming is causing natural disasters , which can be seen all around us. One of the causes of global warming is the extreme release of greenhouse gases that become trapped on the earth’s surface, causing the temperature to rise. Similarly, volcanoes contribute to global warming by spewing excessive CO2 into the atmosphere.

The increase in population is one of the major causes of Global Warming. This increase in population also leads to increased air pollution . Automobiles emit a lot of CO2, which remains in the atmosphere. This increase in population is also causing deforestation, which contributes to global warming.

The earth’s surface emits energy into the atmosphere in the form of heat, keeping the balance with the incoming energy. Global warming depletes the ozone layer, bringing about the end of the world. There is a clear indication that increased global warming will result in the extinction of all life on Earth’s surface.

Also Read: Land, Soil, Water, Natural Vegetation, and Wildlife Resources

Solutions for Global Warming

Of course, industries and multinational conglomerates emit more carbon than the average citizen. Nonetheless, activism and community effort are the only viable ways to slow the worsening effects of global warming. Furthermore, at the state or government level, world leaders must develop concrete plans and step-by-step programmes to ensure that no further harm is done to the environment in general.

Although we are almost too late to slow the rate of global warming, finding the right solution is critical. Everyone, from individuals to governments, must work together to find a solution to Global Warming. Some of the factors to consider are pollution control, population growth, and the use of natural resources.

One very important contribution you can make is to reduce your use of plastic. Plastic is the primary cause of global warming, and recycling it takes years. Another factor to consider is deforestation, which will aid in the control of global warming. More tree planting should be encouraged to green the environment. Certain rules should also govern industrialization. Building industries in green zones that affect plants and species should be prohibited.

Also Read: Essay on Pollution

Effects of Global Warming

Global warming is a real problem that many people want to disprove to gain political advantage. However, as global citizens, we must ensure that only the truth is presented in the media.

This decade has seen a significant impact from global warming. The two most common phenomena observed are glacier retreat and arctic shrinkage. Glaciers are rapidly melting. These are clear manifestations of climate change.

Another significant effect of global warming is the rise in sea level. Flooding is occurring in low-lying areas as a result of sea-level rise. Many countries have experienced extreme weather conditions. Every year, we have unusually heavy rain, extreme heat and cold, wildfires, and other natural disasters.

Similarly, as global warming continues, marine life is being severely impacted. This is causing the extinction of marine species as well as other problems. Furthermore, changes are expected in coral reefs, which will face extinction in the coming years. These effects will intensify in the coming years, effectively halting species expansion. Furthermore, humans will eventually feel the negative effects of Global Warming.

Also Read: Concept of Sustainable Development

Sample Essays on Global Warming

Here are some sample essays on Global Warming:

Essay on Global Warming Paragraph in 100 – 150 words

Global Warming is caused by the increase of carbon dioxide levels in the earth’s atmosphere and is a result of human activities that have been causing harm to our environment for the past few centuries now. Global Warming is something that can’t be ignored and steps have to be taken to tackle the situation globally. The average temperature is constantly rising by 1.5 degrees Celsius over the last few years.

The best method to prevent future damage to the earth, cutting down more forests should be banned and Afforestation should be encouraged. Start by planting trees near your homes and offices, participate in events, and teach the importance of planting trees. It is impossible to undo the damage but it is possible to stop further harm.

Also Read: Social Forestry

Essay on Global Warming in 250 Words

Over a long period, it is observed that the temperature of the earth is increasing. This affected wildlife, animals, humans, and every living organism on earth. Glaciers have been melting, and many countries have started water shortages, flooding, and erosion and all this is because of global warming. 

No one can be blamed for global warming except for humans. Human activities such as gases released from power plants, transportation, and deforestation have increased gases such as carbon dioxide, CFCs, and other pollutants in the earth’s atmosphere.                                              The main question is how can we control the current situation and build a better world for future generations. It starts with little steps by every individual. 

Start using cloth bags made from sustainable materials for all shopping purposes, instead of using high-watt lights use energy-efficient bulbs, switch off the electricity, don’t waste water, abolish deforestation and encourage planting more trees. Shift the use of energy from petroleum or other fossil fuels to wind and solar energy. Instead of throwing out the old clothes donate them to someone so that it is recycled. 

Donate old books, don’t waste paper.  Above all, spread awareness about global warming. Every little thing a person does towards saving the earth will contribute in big or small amounts. We must learn that 1% effort is better than no effort. Pledge to take care of Mother Nature and speak up about global warming.

Also Read: Types of Water Pollution

Essay on Global Warming in 500 Words

Global warming isn’t a prediction, it is happening! A person denying it or unaware of it is in the most simple terms complicit. Do we have another planet to live on? Unfortunately, we have been bestowed with this one planet only that can sustain life yet over the years we have turned a blind eye to the plight it is in. Global warming is not an abstract concept but a global phenomenon occurring ever so slowly even at this moment. Global Warming is a phenomenon that is occurring every minute resulting in a gradual increase in the Earth’s overall climate. Brought about by greenhouse gases that trap the solar radiation in the atmosphere, global warming can change the entire map of the earth, displacing areas, flooding many countries, and destroying multiple lifeforms. Extreme weather is a direct consequence of global warming but it is not an exhaustive consequence. There are virtually limitless effects of global warming which are all harmful to life on earth. The sea level is increasing by 0.12 inches per year worldwide. This is happening because of the melting of polar ice caps because of global warming. This has increased the frequency of floods in many lowland areas and has caused damage to coral reefs. The Arctic is one of the worst-hit areas affected by global warming. Air quality has been adversely affected and the acidity of the seawater has also increased causing severe damage to marine life forms. Severe natural disasters are brought about by global warming which has had dire effects on life and property. As long as mankind produces greenhouse gases, global warming will continue to accelerate. The consequences are felt at a much smaller scale which will increase to become drastic shortly. The power to save the day lies in the hands of humans, the need is to seize the day. Energy consumption should be reduced on an individual basis. Fuel-efficient cars and other electronics should be encouraged to reduce the wastage of energy sources. This will also improve air quality and reduce the concentration of greenhouse gases in the atmosphere. Global warming is an evil that can only be defeated when fought together. It is better late than never. If we all take steps today, we will have a much brighter future tomorrow. Global warming is the bane of our existence and various policies have come up worldwide to fight it but that is not enough. The actual difference is made when we work at an individual level to fight it. Understanding its import now is crucial before it becomes an irrevocable mistake. Exterminating global warming is of utmost importance and each one of us is as responsible for it as the next.  

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Essay on Global Warming UPSC

Always hear about global warming everywhere, but do we know what it is? The evil of the worst form, global warming is a phenomenon that can affect life more fatally. Global warming refers to the increase in the earth’s temperature as a result of various human activities. The planet is gradually getting hotter and threatening the existence of lifeforms on it. Despite being relentlessly studied and researched, global warming for the majority of the population remains an abstract concept of science. It is this concept that over the years has culminated in making global warming a stark reality and not a concept covered in books. Global warming is not caused by one sole reason that can be curbed. Multifarious factors cause global warming most of which are a part of an individual’s daily existence. Burning of fuels for cooking, in vehicles, and for other conventional uses, a large amount of greenhouse gases like carbon dioxide, and methane amongst many others is produced which accelerates global warming. Rampant deforestation also results in global warming as lesser green cover results in an increased presence of carbon dioxide in the atmosphere which is a greenhouse gas.  Finding a solution to global warming is of immediate importance. Global warming is a phenomenon that has to be fought unitedly. Planting more trees can be the first step that can be taken toward warding off the severe consequences of global warming. Increasing the green cover will result in regulating the carbon cycle. There should be a shift from using nonrenewable energy to renewable energy such as wind or solar energy which causes less pollution and thereby hinder the acceleration of global warming. Reducing energy needs at an individual level and not wasting energy in any form is the most important step to be taken against global warming. The warning bells are tolling to awaken us from the deep slumber of complacency we have slipped into. Humans can fight against nature and it is high time we acknowledged that. With all our scientific progress and technological inventions, fighting off the negative effects of global warming is implausible. We have to remember that we do not inherit the earth from our ancestors but borrow it from our future generations and the responsibility lies on our shoulders to bequeath them a healthy planet for life to exist. 

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Climate Change and Global Warming Essay

Global Warming and Climate Change are two sides of the same coin. Both are interrelated with each other and are two issues of major concern worldwide. Greenhouse gases released such as carbon dioxide, CFCs, and other pollutants in the earth’s atmosphere cause Global Warming which leads to climate change. Black holes have started to form in the ozone layer that protects the earth from harmful ultraviolet rays. 

Human activities have created climate change and global warming. Industrial waste and fumes are the major contributors to global warming. 

Another factor affecting is the burning of fossil fuels, deforestation and also one of the reasons for climate change.  Global warming has resulted in shrinking mountain glaciers in Antarctica, Greenland, and the Arctic and causing climate change. Switching from the use of fossil fuels to energy sources like wind and solar. 

When buying any electronic appliance buy the best quality with energy savings stars. Don’t waste water and encourage rainwater harvesting in your community. 

Also Read: Essay on Air Pollution

Tips to Write an Essay

Writing an effective essay needs skills that few people possess and even fewer know how to implement. While writing an essay can be an assiduous task that can be unnerving at times, some key pointers can be inculcated to draft a successful essay. These involve focusing on the structure of the essay, planning it out well, and emphasizing crucial details.

Mentioned below are some pointers that can help you write better structure and more thoughtful essays that will get across to your readers:

• Prepare an outline for the essay to ensure continuity and relevance and no break in the structure of the essay
• Decide on a thesis statement that will form the basis of your essay. It will be the point of your essay and help readers understand your contention
• Follow the structure of an introduction, a detailed body followed by a conclusion so that the readers can comprehend the essay in a particular manner without any dissonance.
• Make your beginning catchy and include solutions in your conclusion to make the essay insightful and lucrative to read
• Reread before putting it out and add your flair to the essay to make it more personal and thereby unique and intriguing for readers  

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Ans. Both natural and man-made factors contribute to global warming. The natural one also contains methane gas, volcanic eruptions, and greenhouse gases. Deforestation, mining, livestock raising, burning fossil fuels, and other man-made causes are next.

Ans. The government and the general public can work together to stop global warming. Trees must be planted more often, and deforestation must be prohibited. Auto usage needs to be curbed, and recycling needs to be promoted.

Ans. Switching to renewable energy sources , adopting sustainable farming, transportation, and energy methods, and conserving water and other natural resources.

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Digvijay Singh

Having 2+ years of experience in educational content writing, withholding a Bachelor's in Physical Education and Sports Science and a strong interest in writing educational content for students enrolled in domestic and foreign study abroad programmes. I believe in offering a distinct viewpoint to the table, to help students deal with the complexities of both domestic and foreign educational systems. Through engaging storytelling and insightful analysis, I aim to inspire my readers to embark on their educational journeys, whether abroad or at home, and to make the most of every learning opportunity that comes their way.

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This was really a good essay on global warming… There has been used many unic words..and I really liked it!!!Seriously I had been looking for a essay about Global warming just like this…

Thank you for the comment!

I want to learn how to write essay writing so I joined this page.This page is very useful for everyone.

Hi, we are glad that we could help you to write essays. We have a beginner’s guide to write essays ( https://leverageedu.com/blog/essay-writing/ ) and we think this might help you.

It is not good , to have global warming in our earth .So we all have to afforestation program on all the world.

thank you so much

Very educative , helpful and it is really going to strength my English knowledge to structure my essay in future

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Global warming is the increase in 𝓽𝓱𝓮 ᴀᴠᴇʀᴀɢᴇ ᴛᴇᴍᴘᴇʀᴀᴛᴜʀᴇs ᴏғ ᴇᴀʀᴛʜ🌎 ᴀᴛᴍᴏsᴘʜᴇʀᴇ

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How do scientists know climate change is happening?

By FactCheck.org

Posted on March 26, 2024

Multiple   lines   of   evidence , including measurements of a  variety of planetary indicators , show that climate change is happening and is  caused primarily  by human activity. As the concentration of carbon dioxide and other heat-trapping gases in the atmosphere has increased —  much of it  from burning fossil fuels — land and ocean temperatures have risen, along with sea levels, while sea and land ice have declined.

The changes are consistent with the basic physics of the greenhouse effect that have been understood since the mid-1800s and  map to what is expected  from human activity. Importantly, the warming of the planet, which is  far more rapid  than anything experienced in many millennia,  cannot be  explained by natural variations in the climate, despite claims to the contrary.

Scientists also know that fossil fuels are the main source of the carbon dioxide  because of the   chemical signature  of the molecules in the atmosphere.

The evidence for climate change is overwhelming. As NASA  says , there is “unequivocal evidence that Earth is warming at an unprecedented rate” and that human activity “is the principal cause.” The 2023 National Climate Assessment similarly  states , “Human activities—primarily emissions of greenhouse gases from fossil fuel use—have unequivocally caused the global warming observed over the industrial era.”

News from the Columbia Climate School

How We Know Today’s Climate Change Is Not Natural

Last week, the House Committee on Science, Space and Technology, chaired by climate contrarian Lamar Smith, R-Texas, held a hearing on climate science. The hearing featured three scientists who are dubious about the conclusions of the majority of climate scientists, and climate scientist Michael Mann, best known for his “hockey stick graph” of temperatures over the last thousand years illustrating the impact of humans on global warming.

This week, Scott Pruitt, Environmental Protection Agency administrator, who had said that human activity was not the primary contributor to global warming, acknowledged that it plays a role—but stressed the need to figure out exactly how much of one.

Despite the many climate “skeptics” in key positions of power today, 97 percent of working climate scientists agree that the warming of Earth’s climate over the last 100 years is mainly due to human activity that has increased the amount of greenhouse gases in the atmosphere . Why are they so sure?

Earth’s climate has changed naturally over the past 650,000 years, moving in and out of ice ages and warm periods. Changes in climate occur because of alterations in Earth’s energy balance, which result from some kind of external factor or “forcing”—an environmental factor that influences the climate. The ice ages and shifting climate were caused by a combination of changes in solar output, Earth’s orbit, ocean circulation, albedo (the reflectivity of the Earth’s surface) and makeup of the atmosphere (the amounts of carbon dioxide and other greenhouse gases such as water vapor, methane, nitrous oxide and ozone that are present).

Scientists can track these earlier natural changes in climate by examining ice cores drilled from Greenland and Antarctica, which provide evidence about conditions as far back as 800,000 years ago. The ice cores have shown that rising CO2 levels and rising temperatures are closely linked.

Scientists also study tree rings, glaciers, pollen remains, ocean sediments, and changes in the Earth’s orbit around the sun to get a picture of Earth’s climate going back hundreds of thousands of years or more.

Today, CO2 levels are 40 percent higher than they were before the Industrial Revolution began; they have risen from 280 parts per million in the 18 th century to over 400 ppm in 2015 and are on track to reach 410 ppm this spring.

In addition, there is much more methane (a greenhouse gas 84 times more potent than CO2 in the short term) in the atmosphere than at any time in the past 800,000 years—two and a half times as much as before the Industrial Revolution. While some methane is emitted naturally from wetlands, sediments, volcanoes and wildfires, the majority of methane emissions come from oil and gas production, livestock farming and landfills.

Global temperatures have risen an average of 1.4˚ F since 1880. Sea ice in the Arctic has thinned and decreased in the last few decades; the Greenland and Antarctic ice sheets are decreasing in mass. The North and South Poles are warming faster than anywhere else on Earth. Glaciers are retreating on mountains all over the world. Spring snow cover in the Northern Hemisphere has decreased over the last 50 years.

The number of record-breaking hot temperatures in the U.S. is on the rise. Oceans are the warmest they have been in a half-century; the top layer is warming about 0.2˚F per decade. The oceans are also 30 percent more acidic than they were at the start of the Industrial Revolution because they are absorbing more CO2. Global sea levels rose an average of 6.7 inches in the last century, and in the last 10 years, have risen almost twice as fast.

Here is how scientists know that the climate change we are experiencing is mainly due to human activity and not a result of natural phenomenon.

Gavin Schmidt, director of National Aeronautics and Space Administration’s Goddard Institute for Space Studies , said that scientists look at a lot of different things at once.

“We have a very, very clear understanding that the amount of heat in the ocean is increasing—the ocean heat content is going up by a lot,” said Schmidt. “That implies that there must be an external change in the radiation budget of the earth—more energy has to be going in than leaving.

“There are a number of ways that can happen, but each of them has a different fingerprint. If the sun were brighter, we would see warming all the way up through the atmosphere from the surface to the stratosphere to the mesosphere. We don’t see this. We see instead warming at the surface, cooling in the stratosphere, cooling in the mesosphere. And that’s a signature of greenhouse gas forcing, it’s not a signature of solar forcing. So we know it’s not solar.”

Moreover, according to the World Radiation Center, the sun’s radiation has not increased since at least 1978 (when satellite monitoring began) though global temperatures over the last 30 years have continued to rise.

In addition, the lower atmosphere (troposphere), which is absorbing the CO2 and expanding as it gets warmer, is pushing the boundary between the troposphere and the stratosphere upwards. If the sun’s radiation were the main factor responsible for Earth’s warming, both atmosphere layers would likely be warming and this would not occur.

Scientists also can distinguish between CO2 molecules that are emitted naturally by plants and animals and those that result from the burning of fossil fuels. Carbon molecules from different sources have different numbers of neutrons in their nuclei; these different versions of molecules are called isotopes. Carbon isotopes derived from burning fossil fuels and deforestation are lighter than those from other sources. Scientists measuring carbon in the atmosphere can see that lighter carbon molecules are increasing, corresponding to the rise in fossil fuel emissions.

Peter de Menocal, dean of science at Columbia University and founding director of Columbia’s Center for Climate and Life , studies deep-sea sediments to understand past climate change.

“Ocean sediments provide a longer term baseline [tens of millions of years] that allows you to compare the past with the present, giving you an idea of how variable ocean temperatures have been before we had thermometers,” said de Menocal. “Over the last 2,000 years, there have been natural climate variations, but they were not especially large…the Medieval Warm period around 1,000 years ago, and the little ice age which was three separate cooling periods lasting a few decades each, beginning around 1300 to around the 1850s. It’s the warming after the 1850s that’s been really remarkable and unique over the last couple of millennia—you can see that in the sediment cores.”

Evidence from ocean sediments, ice cores, tree rings, sedimentary rocks and coral reefs show that the current warming is occurring 10 times faster than it did in the past when Earth emerged from the ice ages, at a rate unprecedented in the last 1,300 years.

To understand this rapid change in climate, scientists look at data sets and climate models to try to reproduce the changes that have already been observed. When scientists input only natural phenomena such as the sun’s intensity, changes in the Earth’s orbit and ocean circulation, the models cannot reproduce the changes that have occurred so far.

“We have independent evidence that says when you put in greenhouse gases, you get the changes that we see,” said Schmidt. “If you don’t put in greenhouse gases, you don’t. And if you put in all the other things people think about—the changes in the earth’s orbit, the ocean circulation changes, El Niño, land use changes, air pollution, smog, ozone depletion—all of those things, none of them actually produce the changes that we see in multiple data sets across multiple areas of the system, all of which have been independently replicated.” In other words, only when the emissions from human activity are included, are the models and data sets able to accurately reproduce the warming in the ocean and the atmosphere that is occurring.

“Today, almost 100 percent [plus or minus 20 percent] of the unusual warmth that we’ve experienced in the last decade is due to greenhouse gas emissions,” said de Menocal.

Findings from NASA’s Goddard Institute for Space Studies show clearly how much natural and manmade factors contribute to global warming.

Climate deniers offer a variety of bases for their skepticism without providing scientific evidence. The most effective thing that the climate denier community has done, however, is to spread the notion of uncertainty about climate change, and use it as an excuse not to take any action.

“It’s been a very effective tactic,” said de Menocal, “in part because the scientific community spends a tremendous amount of effort quantifying that uncertainty. And so we make it plain as day that there are things we’re certain about, and things we’re uncertain about. There are places of debate that exist in the community. That’s the scientific process. … The deniers are not selling a new way of looking at the problem, they’re selling doubt, and it’s very easy to manufacture doubt.”

“They are in total denial of the evidence that there is,” said Schmidt. “When I challenge them to produce evidence for their attributions, all I get is crickets. There’s no actual quantitative evidence that demonstrates anything. … Show me the data, show me your analysis.”

“There are lot of things that we’re absolutely certain about,” said de Menocal. “We’re absolutely certain carbon dioxide is rising in the atmosphere. We’re absolutely certain it’s warming the planet and we’re absolutely certain that it’s acidifying the oceans.”

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I am quite surprised that members of “the flat earth society” have not made any comment on this article……..as yet. Thank you for the informative article, that clearly shows, that Climate Change, which our “spaceship” earth is undergoing is not natural………in fact far from it. As pointed out the proof is a scientific fact………and is certainly backed up, for example, by NASA’s “Operation Ice Bridge” and other scientific bodies and scientists involved in their specific areas of expertise.

This is an old post now but the findings were current then. Firstly the figures in this article are correct and climate change is accelerating unnaturally, I do not deny this as possibly now more than ever human intervention is changing natural circumstances. This said there have been massive swings in tempretature in the planets history which is evidenced in the core samples mentioned in this article and many more since also.

This means that swings will come and go in the planets future, we may survive and other animals to but we can’t save it all, the earths biosphere has and always will be in a state of flux, surviving the knock on effects of this change should be our main focus not trying to recreate a moment in the earths history which is arrogant and short sited.

To stand still is to lose inertia. It’s not nice and probably not even humane but China understand this. Some can be saved, others pave the way that is the only truth in existence. If we look to deeply at carbon emissions we will lose focus in other more important survival projects as public perception breeds state spending in the West. We as 1st world citizens need to lobby for many solutions for many problems not get stuck dogmatically chasing a goal of futility.

I hope this helps anyone reading to gain a little perspective on the issue, change is needed but protection is better than prevention when dealing with the inevitability of change on this amazing very rare extremely valuable planet that is our home.

Yes, this is an old post…But, as always, they forget to mention the fact that a single volcanic eruption produces more CO2 than man has produced since the start of the industrial age. When they can figure out how to stop them from happening, well, I rest my case.

Did you miss the part in this article that explains how they can tell the difference between natural CO2 and man made/caused/influenced CO2? Consider going back and rereading that part.

Michelle, you are missing the point. Assuming the amount of CO2 is increasing, the question is whether that is the cause of “global warming.” This article, like all discussion on this issue, fails to explain this. And if what Darren is saying is correct, then it seems to go against such a conclusion without explaining why the CO2 from fossil fuels is more prone to cause “global warming” than CO2 from other sources.

If you look at historical CO2 levels over millions of years our CO2 levels are 100’s times less, they decreased naturally through two processes, lessening volcanic activity and forests, we are too focused on blame and human CO2 production alone than the fact that FORESTs are our savior, we need a more balanced approach, promotion of increasing Earths forests, decreasing human CO2 creation and monitoring of natural processes. The evidence does not support Man is 100% responsible for global warming but it does support a theory that it PREVENTED a cycle of extreme cooling, an ice age.

Agree with you. The island I live on has had 30 percent of its old growth cut down in 25 years yet the government is ok with this because much of the land is replanted with seedlings. Seriously how long does it take for the ecosystems to came back that were previously established in the old growth forests? I witness the trees being cut down on the island I live on while the permafrost melts.

Well the data since late 2016 shows a decrease in global temperature so there’s that pesky fact. And this article completely disregards climate forcing, specifically particle forcing which is the canary in the coal mine. Nothing man has done has prevented an ice age, indeed it appears to be right on track as evidenced by our current low activity solar cycle 25. I believe it’s still snowing in Brazil as I type this in August 2021. Next two decades will show us how fast the cosmos can send us back to the dark ages. With our extremely weak end magnetic field it’s now a matter of when the CME hits and not if, then all that green energy nonsense will be mere yard art.

2016-Hottest year on record 2020-2nd hottest year on record 2019-3rd hottest year on record Exactly what data are you referring to since all of that data was available in August 2021. Clearly your pesky fact is pesky fiction. Also winter-time in Brazil is June thru Sept because they are in the Southern Hemisphere, so snow would likely occur in August, their winter. But I’m sure you already knew that since you seem to have all the answers even if they are FALSE and MISLEADING.

What (data) records are you referring to, is the question! You people aren’t even capable of common sense thinking. Have you ever been taught the scientific method, I wonder.

We are a major factor in the destruction of our forest.. Maybe it is not 100% us but the vast majority. Fighting and blaming isn’t the point here though as much as finding good alternatives and solutions

A molecule of CO2 does what a molecule of CO2 does regardless of from where it came. The article above explains that the increase comes from our activity.

The physics of how radiant energy interacts with gas molecules is a large branch of research well beyond the scope of this article. Starting with Foote and Tyndall back in the 1850s, we have come to understand pretty well how this works. The same science that makes heat seeking missiles possible can be used to calculate the greenhouse effect of CO2. There really isn’t any doubt that more CO2 causes the planet to warm, but explaining why is too large for one article.

Michelle, if you read that part, the claim is that the man-made CO2 is lighter, which means that on a per-particle/molecule basis, man-made C02 contributes LESS to the green house effect than a heavier natural particle.

Aharon, you seem to be conflating “lighter” with “less IR absorption.” I cannot find any articles expressing that carbon molecules of different density (higher or lower number of isotopes) absorb and re-emit infrared radiation differently. If you can find evidence of this, I’d sincerely love to see it. If not, then you cannot correctly assume that the lighter, man-made CO2 contributes less to the greenhouse gas effect.

Isotopic effects related to CO2 are miniscule. Unless one uses high-resolution IR equipment, the absorption of radiation and subsequent emission are non-issues. Whether CO2 is man-made or natural makes no difference on the warming effects. Note also that carbon dioxide is only one greenhouse gas. Other gases, such as CFCs, nitrous oxide, and methane have substantially more profound impacts on warming. These gases are related to synthetic fertilizers and refrigerants, as well as fossil fuels.

How they do they conclude that co2 and climate is linked when the graph of oxygen isotopes in greenland actually shows that 99% of the climate was at 280ppm co2 and yet the climate fluctuated more during low co2. This does not make any sense to an objective onlooker. The co2 being 280ppm during massively fluctuating times actually concludes that co2 and climate are not linked.

Simply not true, According to the U.S. Geological Survey (USGS), the world’s volcanoes, both on land and undersea, generate about 200 million tons of carbon dioxide (CO2) annually, while our automotive and industrial activities cause some 24 billion tons of CO2 emissions every year worldwide.with all do respect you should check your knowledge before you spread rumors. https://www.scientificamerican.com/article/earthtalks-volcanoes-or-humans/

Dear Ben, Apart from the fact – agreed by IPCC – that humankind and all its accoutriments, industry, livestock and transport etc.etc. amounts to only 3% of global CO2 Emmissions, there is something more serious about the science that people should understand. They don’t because the information has not been permitted to be told to you. First remember that the Man-made Global Warming theory depends upon it being the case that the Greenhouse Effect (GE) is a thermally powerful phenomenon which is being increased in that thermal power by the addition of Human CO2 emmissions. One problem that we have to know about first is that there is no empirical evidence for the thermal power of the GE, but whilst it is not normal to accept a theory as truth without empirical verification there are mitigating circumstances here according to IPCC. Both sides of the argument agree that in the absence of our atmosphere the temperature of the Earth would be 33C lower than it is today, which difference is known as the Atmospheric Thermal Enhancement (ATE). Concerning this, IPCC say that since there can be no other explanation for the ATE it proves the potency of the GE and if it was indeed fair to say that there could be no other cause then there should be every support for the IPCC position. The trouble is that there is a definite empirically verifiable – not guesswork based – cause for the ATE. When a gas – any gas – comes under pressure it warms. We know this, oddly enough, because we used to go “ouch~” as children after a bit when we pumped our bike tyres up – this is your unsuspecting knowledge of this characteristic of gas being heated by compression. Our Atmosphere is under a pressure of 1 ton per sq ft so the warming effect is comfortably able to account for the ATE which meanstonishingly – that there is nothing for the GE to account for. Accordingly the there is no thermal consequence to the GE so neither is there for our contribution to it. Hold your breath and count to ten. In my discussion with him a scientist from the Scott Polar Institute conceded that compression does indeed warm gas, but proved unable to advise me of any calculation for it that allowed for any remaining potency in the GE. It means that all temperature variation that we experience is indeed as a result of the constantly changing net insolation. Barley was harvested in Greenland 1000 years ago. The pottiness of this anthropogenic theory; thus revealed: has nevertheless take over global opinion to an extreme extent by spooking us and leaving us to believe what seems safest. I realise that this will come as a shock, so please remember to be strictly scientific in your rebuttal if you think lone exists. If not; as I suspect you will discover: then its time to stand up against bullies who take advantage of our fear and trust to get personal power over us.

I’m genuinely curious if you can explain the cause of the alleged increase in atmospheric pressure you’re referring to, and/or provide some evidence that such an increase exists.

The real problem is the assumption that increases in the Earth’s temperature and the effects caused are a bad thing. Rising sea levels will mean millions of people will be forced to move inland. This is always claimed to be a bad thing. Yet people will adapt by building roads, bridges and new homes. New places to work and shop. It will mean a boom in jobs such as the world has not seen since after WWII. Longer growing seasons, perhaps enough to get 2 crops in per year where now only one is possible. We alwats seem to focus on the bad that might happen, never the good.

tell that to the species going extinct or the poor people homeless and hungry. Wow, must be nice to be privileged and protected by affluence, for now. Eventually, of course, this will affect you too and then your position and opinion will change as our climate has and will continue to do so. Denial on the part of so many is our real problem and it is what keeps us from acting in time.

Interesting, I never heard this theory and it make a lot of sense to me. Did I understand correctly: you mean that compression creates temperature, so irradiation and type of gas has nothing to do with GE. I have a question. If this is true, why is that global temperature does change? It changes in the thousand of years scale and in the decades scale. If it was just the pressure, how we explain these changes. We use other factors like cloud coverage, irradiation, albedo and those things. But, then, also infrared capture (that is GE) can have a role. So aren’t we at square one again?

Pete Rogers we need to be friends

All due respect is the correct phrase.

The scientific evidence begs to differ with you Darren: https://www.climate.gov/news-features/climate-qa/which-emits-more-carbon-dioxide-volcanoes-or-human-activities

No, that is absolutely false. People contribute more to CO2 in the atmosphere than volcanoes.

https://www.usgs.gov/natural-hazards/volcano-hazards/volcanoes-can-affect-climate

Patently false. The CO2 released from volcanic eruptions in total from volcanic eruptions is about 1% of anthropogenic CO2 sources (Reference: United States Geological Survey).

You don’t have a case. If the effect of the total amount of CO2 continuing to rise means extinction for many species, possibly including humans, and volcanoes can’t be stopped; logic has it that it’s that much more crucial that the humans stop contributing to the total amount in any way they can.

They may emit CO2 but at the same time they put huge amount aerosols into atmosphere which leads to cooling immediately after eruption and as a matter of fact they’re more beneficial.

The elephant in the room is over population. Too many people equals too much pollution. Simple and true.

You seem to be suggesting, quite logically, that humanity, like all other dominant life-forms of previous eras, is doomed to eventual extinction. I agree it is irrational hubris to think otherwise. If that is indeed the case, perhaps we should put more effort into making human lives less miserable, while we’re still here. The idea that the way to do this is to simply help humans make more money is demonstrably false. The most effective way to do this is to improve health and wellbeing. The latter has more to do with how we treat each other and how we educate people to cope emotionally with adversity and pain.

Just curious. What is your data source? How do you know climate change is accelerating yet your average meteorologist can’t predict the weather beyond 5 days? Climate is a bit more complex than core samples. Man landed on the moon 52 years ago, yet we are masters of the universe? Hardly. The Earth is 95% uninhabited and has had cycles of both extreme heat and cold far in excess of what you’re discussing. Palms at the pole? Iceball Earth? Both happened. I disagree that we know what Earth’s climate is or will be, and I see a lot of hysteria from people parroting the latest on climate change without citing sources or defining “normal.”

A kindred spirit. Good for you. I’m receptive to anything that has a coherent rationale supported by sound argument from reliable data. The Hockey Stick has none of that. In the absence of compelling evidence to the contrary, the null hypothesis tells us to expect things to continue much as they have. The world will gently warm. Sea levels will slowly rise. Carbon will continue on its upward trajectory. The earth will continue to get greener and more hospitable to life. Biomass will increase. The past three decades have been just about what you would expect from our experience over the last few centuries, with the exception of CO2 concentration. The last three decades have unfolded as I expected they would. They have very much not unfolded as predicted by the Hockey Stick. Extrapolating that curve forward gives a ridiculous value for the present day. Unbelievably, despite the fact that empirical data everybody can see flatly contradicts it, people raising the climate alarm swear the Hockey Stick is still true. This sorry episode in the history of science can’t end quick enough for me.

if you believe the world is warming and becoming greener or more livable then you clearly have not been paying attention to the weather the past few years.

How can you look at the constant forest fires in the pacific north west and Australia and rising ocean temps contributing to the death of the coral reefs the shrinking of glaciers all over the world and think were entering an age that is more hospitable to life? It may be natural for temperatures to rise but it is happening at an unnatural rate and that is clearly linked to man made CO2 emissions

The Hockey Stick doesn’t predict anything. It’s a graph of the past indicating trend lines in temperature. What that means in actual consequences we won’t know for sure until we are in the middle of it. But there is a 10 – 20yr lag from cause to effect, meaning the next decade is already cooked in based on what already occurred the prior 10 years. Could this be why it’s not as it seems to you? It seems to me that by 2050 it will be undeniable. Now since the earth is a dynamic system, and living organisms are opportunistic, those that utilize C02 could somehow thrive and snap us back into a cooling period or massive volcanic activity could do that as well. But those seem highly unlikely. We’ll have to wait and see, but by then it could be too late.

Outstanding post. Rationale balanced thoughtful and possible.

It’s true what you say, but issues have to be dealt with in some order and climate is the first thing and it’s a unifying issue. Planet /people before profit must be included on the list and that together with Climate Change will start to solve most issues and good first steps. What else really matters?

At one time in history the best available knowledge was that the Earth was flat so please do not attempt to ridicule people with that term.The 97 % consensus is meaningless. Only 100 % agreement becomes best available knowledge.

There will never be 100% agreement because there are inevitably people that are greedy enough to lie about the science bc some thinktank tied to the oil industry is paying them the big bucks to say what keeps them making the greatest amount of profit. We know this to be true because you’ll see such and such climate denier and sometimes you can follow the money trail to politicians or oil industrialists that benefit from climate denial.

That’s the problem with wanting it to be unanimous. If there is an expectation of all scientists being rational and reasonable, when an industry that makes tons of money is involved, it is naive as anything, because human greed will always factor in. Anytime $$$ is involved in a situation, you will find a soulless shill that only cares about their thirty pieces of silver.

Therefore, you have to expect hold outs and need to judge by the /majority/. Were the majority response to be 60/50 or 50/50 it is far less of a sure thing. Even 70%, we would need to work more just to make sure it wasn’t founded on bad science. 97% more than accounts for the truth, and the 3% reasonably accounts for both the incompetents and those who only care about their self-interest.

To ignore human greed, to expect everyone in a situation to be noble and truthful and purely rationable, is to be completely naive about human nature. It’s a /child’s/ view of the world to think you won’t find some people in every situation that care only about self-interest.

97% is also a much higher threshold than many things we hold to be concrete enough to act on in science and medicine.

For instance, in medicine, with psych meds, they barely know why some of them even work. Our knowledge of neuroscience is still a work in progress. But enough people agree on working theories, and have tested meds enough to know that withholding them from people who they can benefit until there is 100% understanding and consensus is impractical. If you have /most/ of the picture and a large majority agree on it, and some of it is testable, it’s worth taking action on.

In the case of climate change, there’s also just the general practicality of moving to renewable sources of energy when we know even more unequivocally that fossil fuels are finite resources because of the way they were created, and that we’re better off moving to new energy sources for other reasons anyway. The resistance to renewables when 97% of climate scientists agree, but /also/ we’re going to eventually run out of fossil fuels (it’s more practical to transition many decades ahead of shortages to avoid strain on infrastructure), /and/ renewables lead to cheaper energy bills for the average consumer? Is ridiculous.

In a situation where there are /many/ reasons it’d be practical to make the change sooner rather than later, even if climate change /was/ a hoax or bad science, we need to think about WHO benefits from stalling it?

The fossil fuel industry and the politicians whose election funds they donate to. Full stop.

97% is plenty.

A 97% consensus would be phenomenal, statistically speaking. Anything over 95% confidence in statistics is gold standard. Achieving 100% would be futile and a waste of time to convince the other 3%. But it could be fun.

Bloomberg has a series of global temperature graphics that nicely illustrates the relative contributions of the various forcings:

https://www.bloomberg.com/graphics/2015-whats-warming-the-world/

It’s not been updated to cover the last two years, unfortunately, but the human component is clear to see.

“Earth’s climate has changed naturally over the past 650,000 years, moving in and out of ice ages and warm periods. Changes in climate occur because of alterations in Earth’s energy balance, which result from some kind of external factor or “forcing”—an environmental factor that influences the climate.”

Some kind of external factor? This doesn’t sound definitive.

@Kurlis I don’t think this article is trying to be definitive about natural causes of climate change in the past. The rest of that paragraph does go on to list them, but they’re not the main focus. The author is just making the point that we know quite a lot about them now, so we understand that their role in the present climate change is fairly small. By far the greatest part of what we are experiencing now is human-induced.

Thank you for your amazing article 🙂

I just can’t bring myself to trust people this much. Science is always right…until they discover something new and realize they were wrong the whole time. It took 200 years to graduate from Newton’s Law to Einstein. Everyone used to believe that the world was flat…. and they were wrong. Just one or two incorrect interpretations, lead the whole theory off course. I do not know. I guess the science community better hurry up and figure out how to create affordable sustainable energy and figure out how to create animals that won’t poop or we’ll all be dead in a few years. Funny though, such a push to ‘civilize’ the uncivilized. Only to figure out that civilization kills us all. Crap, wrong…again.

It’s a myth that people used to believe the earth was flat.

No, it’s a myth that people in the time of Columbus believed the earth was flat…it was stated as a sphere by ancient Greek scholars.

In the 1960’s, ALL scientific experts claimed the hole in the ozone layer was going to destroy the earth and make it inhabitable for humans due to increased temperatures and higher UV ratings making the earth into a hot house. For years it was sprouted as fact and people were encouraged to stop using spray cans and they stopped using CFC’s. It was front page news for a few years and FACT until they discovered the hole in the ozone layer can never increase. All of a sudden, all was quiet! But, the hysteria was real and scientific experts convinced EVERYONE it was fact because they were the experts. I’m not saying scientists are wrong but the exact same thing happened in the 60’s as is happening now except now we have the internet and kids who have a louder voice.

The amount of ozone loss was testable. You realize you can measure ozone, right?

They were wrong about it being as dire as all that, but they were right about the heightened risk of cancer and cataracts and the hole was capable of shrinking, and general ozone levels were able to be increased by ceasing CFC.

Ceasing CFC use didn’t harm the world at all, it was just an inconvenience and it was worth it for a lower skin cancer and cataract risk.

I see people citing “Well no one talks about that anymore!” The reason people stopped talking about it was also that it was pretty much fixed through worldwide effort.

Something we’re clearly incapable of now.

Except now we have glaciers melting at accelerating rates; species migrating to new latitudes to get away from unsurvivable temperatures; plants blooming in January – February, and uncoordinated timing of food supply for birds and insects; and mangroves endangered by encroaching salt water.

No one talks about it now because the problem was solved. It was a real danger; unless you want to live indoors your whole life. Well, we got a taste of it during Covid so we know how that went. But this shows when humanity is united and agrees to changing behavior, we can solve our problems.

What exactly of Newtons law are you speaking on??? It took him under 2 years to %100 prove gravity. Imagine if he had to explain it for over 130 to morons like climatologist have???

True! Science can always be wrong. But it gets less and less wrong all the time, and, even if it can be wrong, it’s still the most reliable source we have. We can never have fully, definitely correct answers, so we can only cling to our best estimations. It’s reasonable to be untrusting of science, but there’s nothing we can trust more.

Newton’s law is not incorrect, it just cannot cover things Newton cannot observer at his times, or simply beyond his comprehension. It does not mean it’s wrong under his model. In other word, Newton’s theory explain how the stuff(gravity) is working. Einstein’s theory helps to understand, why the stuff (gravity again).. is working.

The article stated that created models that simulate the current earth climate, and find that man-made, or man emissioned carbon contribute to the current warmer climate, and the result can be duplicated. It means in the current model is correct under these conditions, and that green house gas is the main contributor to the global warming.

Except if you actually look at the models and their history do realize how dubious they are. The models constantly have to be reduced lower because they overestimate the amount of warming that will occur. Plus, these same models often don’t reproduce the correct historical data and have to be manipulated in order to get them to produce the correct historical data.

“Today, almost 100 percent [plus or minus 20 percent] of the unusual warmth that we’ve experienced in the last decade is due to greenhouse gas emissions,” said de Menocal.

I’m still waiting to read the part that proves it’s not natural. Aren’t these the same climate scientists that were warning me that we were headed for an ice age when I was 12?

You’re right, the Earth is actually supposed to be in a cooling phase, because the sun is getting slightly weaker. But the Earth isn’t cooling, and that’s one of the ways scientists know we’re causing the Earth to warm. Here’s a good podcast if you’d like to find out more: https://player.fm/series/heres-the-thing-with-alec-baldwin/climate-science-explained

What about this chart? It looks like we are still in a downward trend. https://www.iceagenow.info/temperatures-have-been-falling-for-the-past-8000-years/

That chart comes from Wikipedia, not a credible scientific journal or organization. How about all of these charts? https://climate.nasa.gov/evidence/ https://climate.nasa.gov/scientific-consensus/ https://royalsociety.org/topics-policy/projects/climate-change-evidence-causes/basics-of-climate-change/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2995507/

Sarah, None of the charts you attached show that it was not warmer 8,000 years ago and 3800 years ago. So maybe the Wikipedia chart is correct about the temperatures back then? So if it was warmer 3800 years ago why is it a bad thing for temperatures to rise today. Insurance rates demonstrate that some people will need to move away from the coast, but perhaps more land will be available further North for agriculture and living. Why is that a bad thing? I’m not sure many people deny global warming, I think that what I’ve heard to suggest that global warming is a bad thing has not been convincing.

It’s a bad thing because the rate of change that is occurring. If this gradually increased over 1000 – 2000yrs as is natural, then most living systems could easily adapt. But this will occur in a matter of 100 – 200yrs. The change on paper is black and white. But the living consequences will be pain,suffering, frustration, and grief. It will be really difficult from keeping the world from plunging into chaos. On thing to keep in mind is that there is a 10-20yr lag from cause to effect. Meaning the previous 10yr actual determines the next 10yr effects. By 2050 it should be undeniable the direction this is going.

Did you know the impact of unnatural climate change do and will differ in both magnitude and rate of change depending on the continent, country, and region. Hence the impact and affects does not only mean global warming,but severe and more frequent hurricanes, cyclones, typhoons, droughts, floods, rain and snow, increase in ocean levels and acidification, melting of the poles, changes in ecosystems,desertification, extinction of non-human animals species, increase in disease,starvation and even death for humans.

Do you have scientific evidence for your claims?

Hi Timmy! I understand that, when looking at this picture, it’s easy to feel sceptical. However, the picture of the magazine issue from 1977 is actually fake – the cover is actually from a 2007 issue, and the title has been photoshopped – it was actually “The Global Warming Survival Guide”, NOT “how to survive the coming ice age”. This meme is very misleading and it can influence whether people have trust in the facts provided by climate scientists, so it’s unfortunate that it’s been falsely spread on social media. The information is here: https://www.apnews.com/afs:Content:5755221200

The meme might be misleading, but the message isn’t. It’s true that scientists were warning of global cooling back in the 70s.

There might have been a few scientists predicting global cooling but most were predicting global warming. Here is an excerpt from an article at the link that follows.

“A survey of peer reviewed scientific papers from 1965 to 1979 show that few papers predicted global cooling (7 in total). Significantly more papers (42 in total) predicted global warming (Peterson 2008). The large majority of climate research in the 1970s predicted the Earth would warm as a consequence of CO2.”

https://skepticalscience.com/ice-age-predictions-in-1970s-intermediate.htm

The most curious fact about these volte faces – perhaps – is that they leave us wondering why we haven’t learned – as a matter of intellectual discipline at the very least – to use a multi-millennial term for the basis of our evidence collection, being the scale appropriate to the judgement of climatic trends bearing in mind that in the end we need to fairly establish what become most likely behaviours in the manner and progression of glacial and interglacial trends. The reason for this is that it’s the only way to cope with short term excursions. Without this longer more balanced term to go by any opportunist can extrapolate from his most helpful short term trend to put the fear of God (so to speak) into an unknowing public so to manufacture fear and so dependence and then conformity. IPCC take the period 1750 to now – 270 years – as if it were the proof ne plus ultra of where we must be going given CO2 inputs. The other side take a thousand years pointing to a Mediaeval Warm period that was warmer than today without our CO2 and an argument then develops about whether there really was such a period whereas if we look at epoch level we see this

which shows cooling since the Holocene 7.500 years ago which is the interglacial peak so far. If we then look at the previous inter glacial periods we should see something not unlike this each time. The temperature rockets up from the glacial depths to reach a maximum after which it wriggles along in a series of warming and cooling peaks and troughs with each warm period failing to surpass the previous peak and each cooling getting lower than the previous one. It means we are cooling when you take such a climatically meaningful span as the basis for evaluation. When we do plummet – something which always happened before – what is going to happen to farmland and crops for instance. I won’t go any further than that, not wishing to provoke fear, but thought. The clincher is – though – that the argument that we are stuck in a man-made warming crisis depends firstly upon it being the case that the Greenhouse Effect (GE) accounts for the Atmospheric Thermal Enhancement (ATE) of 33C, which IPCC claim in itself as proof as they say there can be no other explanation for the way the atmosphere adds warmth to the planet than the GE. Right there before us we see the biggest banana skin in modern scientific history – or I would argue ever – being stepped upon by the bearers of our finest scientific minds because there is indeed another explanation; an obvious one and one which overthrows that claim (for which there has never been a scintilla of empirical evidence incidentally) and that is gravity. Any and every body of gas warms when compressed – because there are then fewer cubic metres to accommodate the heat energy, meaning more heat energy per cubic metre leading to the ATE bearing in mind that gravity leads to a pressure of 1 ton per square foot. That this fact – requiring only pre-college physics – has been missed is catastrophic for the reputation of science and scientists all over the world and something serious must be done to stop its hijacking by politicians. It means the variation in temperature – as ever before – is entirely due to the cycles and alterations in continuous progress leading to fluctuations in net insolation and therefore temperature etc.. We need scientists to release the public mind from the psychological bondage of myth which is its purpose.

Penelope, isn’t it crazy how people just believe anything with out looking into weather it’s real or not, I feel this one the big reason so many people deny this because they see something with no scientific backing and run with it

The Time cover is fake. Check snopes.

According to the natural climate cycle we are suppose to be in a mini-ice age right about now; but that didn’t happen and has scientists alarmed. That is why climate scientists are studying global warming and its causes. So far the evidence is that it’s the result of human activity because nothing else accounts for it. The article discusses parts of this.

Yes I remember the warnings of an ice age too

Can anyone direct me to an official site where I can find out how much money the US government and the IPCC grants scientists who study climate change from natural causes?

I think you’ll find out that’s 0 dollars joking

I can’t find out either

We are suppose to be in a mini-ice age, but unexpectedly global temperatures are increasing. So climate scientists studied the causes. Of course this included studying natural causes as they needed to understand what was happening. Did you read the part about how sun activity was ruled out of consideration?

The average lay person like myself can only listen to both sides and rightly conclude that one side is wrong. I’m going to go out on a limb here and say that the wise choice would be with those whos business is scientifically studying and analizing climatology. Seems that if they have it all wrong, we’re still OK. If the deniers are proven to be off base (wrong), we’ll only be left with the small comfort of saying “I told you so.”

The question I have always had is how accurate are the measurements. Just during my lifetime I have seen tremendous advancements in technology. Then I read how data has to be adjusted to account for these changes. So my big concern is the margin of error in these estimates because we are not taking about huge variations. 1.4 degrees increase since 1880. If the margin of error is .5 degrees then the fluctuation could be 1 degree and we are only talking about 1.4 degrees. Same with sea level rises. How is that measured and does it take into account erosion and shifting sands and shifting tectonic plates. What if fhe earths core is warming and that is causing the oceans to warm thereby emitting more CO2. Just alot of questions. No doubt we need to limit all pollution to try to protect the environment but this doom and gloom scare tactics dont work on me.

Ok i get that it is accelerated 10x by human factors but surely all this is confirms thats it is natural??? The real question is why does nobody seem to be planning for the consequences of this climate change especially as the deadline to respond has been shortened by 10x This includes planning evacuations of low lying countries or building giant flood walls, attempting to combat desertification in any way possible and other areas of possible future disasters Instead all the focus is on slowing down something that as far as i can tell is inevitable

“97 percent of working climate scientists ” Hahaha…

Did you find out how they get this number ??? If you take the time to find out how they get this number you will not use it anymore…If you are a serious person .

The ad hominem references to “deniers” likewise contribute to the credibility of the article.

I’m still waiting for the human forced ice age we were supposedly going to go through… guess what? Climate change IS natural. No scientist in the world can deny that. That must have forgotten history and the age of the first mammals. Guess what? They adapted and evolved. Which is NORMAL. Anyone who believes this garbage is misinformed.

You didn’t read the article, did you? LOL

Yes we all read the article. What the article said is that the scientist forced the outcome in their models by inserting what they deemed to be the cause. Not that it was the cause but that it made the model react to show it was the cause. Now riddle me this: why is nothing being done to preserve our forests which keep the earth’s atmosphere in balance? Why is everyone concentrating on fossil fuels like oil and gas?

It’s natural, yes. The article phrased this incorrectly. The unnatural part is the speed at which human influence is causing it to happen. You could still call this natural, since humans are themselves a part of nature, but it could still cause an extinction event, and even a natural extinction event is a bad thing.

Very simple answer. You dont. And you cant, because you can not set up the required controlled experiment. The rebuttal to this simple fact is usually centered around “but the models”. But models are just that and ade subject to gigo.

Now, that said, I personally believe that human activity IS a significant factor is our planet’s warming trend. But this hypothesis can not be proven. And concensus just means that the vast majority agree, not that they are correct.

Why do all of your studies not show the past 100yr human interference in global warming, that is as long as there’s been fossil fuels all your science evidence has been before, no proof for the past 100yrs. There is no science that proves it’s from fossil fuel, so scientists of the world better be more convincing or the world of humans will not get involved.

Something else that isn’t making Spence is the glaciers melting is uncovering artifacts from humans before fossil fuels, so that is telling us that before fossil fuels we were going into an ice age………the wooly mammoth found was before the last ice age……the ice cores show 15 ice ages 10,000yrs apart, 100yrs ago we were Suppost to go into an ice age, what stopped it??? Al Gore showed the CO2 gragh of the ice ages, the CO2 is higher now than ever before and there is no ice age……..?

CO2 traps heat and warms the earth’s atmosphere, this forces global warming. Plants that use CO2 help cool the earth. If enough plants utilize CO2 faster than it being produced, the earth will stay moderately cool.

my questions out of interest as I have an enquiring mind

what if the earth was moving closer to the sun? or what if the earth is tilting on its axis or what if the universe is expanding or what if the Sun is getting stronger

all questions that I have not seen anyone answer with meaning yet

Very interesting & most telling as to why, no one has answered these relevant Questions, involving Climate concerns beyond CO2 Hype.

What if the Earth is moving closer to the Sun? Technically we are moving away (fractionally on semimajor elliptical) plus it has begun to move cycle from a warm to a cooling cycle. What if the Earth is tilting on its axis? Planet Earth is certainly tilting on its axis,, it also is changing its position at the Poles more shift recent decades., effects; Climate Vortex Winds. .. What if the Universe is Expanding? It has been expanding since the Big Bang as they say. Orbit of Planets around the Sun is elliptical causing long cycles of Heating & Cooling. What if the Sun is getting stronger? Whilst over the long term ; the Sun becomes hotter & brighter. The Sun also goes through short term phases of activity ; we are entering a low.

Alignment of Planets is another factor. Earth is moving away from the Sun in its elliptical Cycle plus the Sun is entering a Cooling Phase.

Climate Change greatest influence , begins beyond our Green House Gases. The Suns activity & proximity is the greater driver for change.

thank you! Inuits and Elders said the same thing

If everyone died today what would happen? China, India etc. are the highest polluters in the world who will never enact policies to lower emissions and will probably attract even more businesses who want lower running costs, hence increase their pollution output. Considering these countries will most likely increase their pollution levels, why is NOTHING being done to rectify this problem and drastically address the worst perpetrators which would be the most effective step when the situation is so dire and immediate! It’s like plugging a small hole while it’s gushing water up the pipe and drowning us and everything in its path.

The ice core samples did not prove that CO2 caused warming. The Ice core samples simply demonstrated that when temperatures were warmer there was higher concentrations of atmospheric CO2. The data does not conclude a casual relationship between CO2 and temperatures. In fact, there is much stronger evidence that higher concentrations of atmospheric CO2 is an effect of higher atmospheric temperatures.

Half fill a bucket with ice and top up with water to top. When the ice melts the bucket does not overflow. They quote NASA but if you go to NASA’S own web page and look you will see that the article is decreasing but the Antarctic ice cap is increasing by more than the artic is decreasing.

not how it works……

Excuse me. But how can you account for all “natural” factors in any model if you don’t start from the assumption that you already know what the anthropogenic factors are? How can you scientifically justify calculating the anthropogenic influence on climate change by subtracting the natural influence on climate change from the total measured climate change, when the natural influence in itself is derived from subtracting the anthropogenic influence on climate change from the total measured climate change in the first place?

Isn’t this a) circular logic and b) horrible science, since the outcome of the research is already taken for granted as an essential part of the foundation of the same research?

Not to poke fun at this logical inconsistency, but how is this different from me making up an arbitrary number concerning a solar factor to climate change, then calculating the non-solar factors to climate change by subtracting my made up solar influence value from the total, and then claiming that I can measurably prove solar climate change by subtracting my natural factor value from the total measured climate change value?

How is this even a remotely credible methodology?

How is shallow ocean data collected? Mainly temperatures

We don’t second guess experts in other fields of science yet, somehow people have the arrogance to question the vast majority of scientists who give us this important information.

Maybe if I bet all my money that a stranger can beat Lebron James one-on-one I’ll get a jackpot, but who would do that even though it’s technically possible? Scott Pruitt proves that regardless of politics he can’t agree to the truth.

I’ll give experts the benefit of the doubt here!

Sir Karl Popper used the concept of “falsifiability” in science. So for example it’s possible to measure the mass of a proton accurately and to continue to repeat the experiment to verify the result.It is not possible however to falsify a prediction using a computer model than the temperature of the earth will increase by 1.5 or 2 degrees by the year 2100. So climate science which relies heavily on computer models doesn’t have the same rigour as say particle physics. It doesn’t mean the predictions are wrong just that there is greater uncertainty in their validity.

Say they are wrong? What’s the problem with changing our general consumption of resources to be less wasteful (when we’re burning through other resources), to make a change to renewables sooner rather than later when fossil fuels are a finite resource we’ll eventually come into conflict over worldwide, when we need to reserve fossil fuels for plastics until we can find replacements for all the variations in plastics as well, and to have cheaper energy sources?

Say we’re overcautious and move to renewables. Silica sand for fiberglass or carbon for carbon fiber turbines are hugely plentiful resources even if the mining process fucks up the land. (Fracking also fucks up the land so we may as well do it for cheaper energy resources).

People forget it’s not JUST about climate, it’s also about consumption and population, and many of the choices done in an abundance of caution for climate change also help mitigate problems from those as well. So we may as well do them.

There are many benefits to warmer climate. 4000 years ago when the temperature was warmer than it is today, areas that are now desert had plenty of water and could be used for agriculture. My biggest problem is the government using deceit to collect taxes on global warming fears.

I am curious. If greenhouse gases truly warm the Earth, why is Mars, with a thinner, mostly CO2 atmosphere, warmer than Earth’s poles or parts of the US on many days? Can any of you describe how Earth will never be like Venus? I noticed that “the Earth has warmed 1.4 degrees Celsius in recent history. Why use 1880 or later? Why not cite temperature averages during the age of the dinosaurs, or prior? Earth was far hotter and more humid with palms at the poles or completely ice-covered at various times in its past. NOAA uses 120 years of data to prove climate change, I saw a reference to 650,000 years of climate data on this site, but the Earth is 4 billion years old. We need more data and understanding to prove the climate change hypothesis. If we can’t predict the local weather in 5-10 days, then how could we expect to predict climate change on an infinitely grander scale going back billions of years? That strikes me as overly ambitious. Please, someone, tell me what normal temperatures are, Don’t just tell me, show me the entire climate history of Earth and prove that changes aren’t consistent with past variations of temperatures during Earth’s history. I am not a Flat Earther, but I do question.

This article states that ice cores over the last 800,000 years show a link between co2 and temperature. 99.9% of the ice core actually shows the earth at 280ppm at massively fluctuating climates. How do they conclude that?

If a person believes that climate change is bad, why would they promote electric cars. Electric cars use electricity made from coal and batteries are an environmental concern.

. If climate change is bad why not promote the use of hydrogen as a fuel for cars. Hydrogen is safe, cheaper than gasoline and non polluting.

If a person believes that climate change is bad why promote wind energy and solar energy which cannot replace coal. Why not promote nuclear energy which is safe, does not create carbon, is abundant and can replace coal?

I question the motives of those who promote electric cars, solar energy and wind energy without promoting the use of hydrogen and nuclear power.

From what I’ve seen and heard…climate activists are promoting a wide range of options including hydrogen and nuclear. However, nuclear energy does present certain risks. A major environmental concern related to nuclear power is the creation of radioactive wastes such as uranium mill tailings, spent (used) reactor fuel, and other radioactive wastes. These materials can remain radioactive and dangerous to human health for thousands of years.

The Hawaiians used to sacrifice a virgin to make the volcano god happy. The aztec priests used to say we need to sacrifice someone to make the rain come. Today they say we need spend billions in grants and federal spending that could be used elsewhere so that we can research climate change. Im not saying climate change doesnt exist, because it has been changing since the beginning of earth. But I am still not convinced that humans have any serious impact on climate change that we should worry about. I am more concerned about plastic in the ocean than climate change or maybe in a 100 years If climate change increased the temperature 1 degree maybe I could grow some bannana trees in my southern californian backyard. Or maybe in 1000 years the temperature will increase 10 degrees but by that time elon musks great great great great great great great grandson invents the magical farting zero emission zero footprint flying car. My point being here is that why should we care? From the perspective of the human existence on earth in a 1000 years plus we will probably have to find new settlements in space anyways like the lack of food and resources on earth and new improvements in technology anything is possible. From a perspective of the next few decades, I think we have bigger problems.

I can’t tell you why you should care about climate change, but I can tell you why plenty of people do: Because climate change is already costing us hundreds of billions of dollars in damages from natural disasters, and because human lives are at stake. We can dream about escaping to other planets, but the reality is that fixing those planets to fit our needs would be harder than fixing the planet we already have. We know what the problems are, we know what the solutions are, and now all we need is to be brave enough to implement them.

I think it is true that the greatest loss of life from a natural disaster if the US occured in Galveston in 1900. It is estimated 12000 people were killed. I would not speculate on the cause of the hurricane.

Cool facts, bro. Doesn’t change the fact that climate change is making deadly disasters more common

And how do we know that climate change is causing the natural disasters? And where would I find verification for hundreds of Billions. What about the money saved from decreased heating bills? Since 1990 the amount of foliage has greatly increased. I would be interested in seeing a study examining the beneficial affects to the rain forests. Food production has dramatically increased since 1990 because of the warmer growing season. If the adverse affects are so extensive why aren’t politicians clamoring for increased nuclear and hydrogen power? The politicians like to collect carbon taxes, but why do they do something that causes real benefits?

repairing billions of dollars worth of damage keeps people busy that would otherwise just do other useless stuff instead of creating wealth furthermore 9While I am at it) we have many problems on this earth at least as large as Climate Change and none of them are on the big list of Mitigation ie rising Rates of Suicides rising rates from Drug overdoses many Nations spending trillions preparing for more Wars many Nations at War when are we going to deal with alml that?

“We’re absolutely certain carbon dioxide is rising in the atmosphere. We’re absolutely certain it’s warming the planet and we’re absolutely certain that it’s acidifying the oceans.”

“Doubt is not a pleasant condition, but certainty is absurd.” — Voltaire

Just the word absolutely nullifies your supposed point!

It’s been said that only fools believe that changing the climate is possible by giving money to the government!

Well I’m no scientist but why is the southern hemisphere on their map cold while the rest of the world is hot? Doesn’t our atmosphere encircle the whole earth???

Measure the increase in carbon emitted from undersea and above-ground-level volcanoes. Volcanic activity is increasing due to changes in the universal activity that has always driven the changes to our environment. Mankind’s impact is minuscule compared to the volcanic release of carbon that is often not calculated honestly and can skew any report in favour of the organisation funding the research. Do the volume comparisons. Scientists would not ever work again if they failed to deliver the result their financiers required. They can always find another desperate scientist with a mortgage to corrupt. By the way, it is not that we don’t want any action as you falsely claim it is an action that improves life and, not an action that helps the Globalist banker control commodities prices that we aspire to take. The alternative industry creates more pollution and toxic waste from short term batteries and panels, carbon blades and other filthy short life overpriced materials pushed by your ridiculous ideology. Be honest and think it thru without your bias. Short life throw away toxic battery car

My first question is, if we keep having year after year heat records, how come the last record minimum artic ice was almost 10 years ago? Like Ice in your drink the warmer it gets the less ice we have.

https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/?fbclid=IwAR1fC1dpq5gv8jw3Ozw36iIF0GagXvCenfJ-UOuzvFDGWYakJ-zsRXNHEZ4

My second question is if this is the warmest temperatures in thousands of years, why are the retreating glaciers exposing human remains, roman coins and “Viking highways”? These artifacts suggest it was warmer in recent times and a colder recent climate covered them over.

https://www.theweathernetwork.com/ca/news/article/lost-viking-highway-and-artifacts-revealed-by-melting-glaciers-in-norway

Why is homogenizing the temperature data the correct way to show the temperature record, wouldn’t the raw data average out the outliers?

https://data.giss.nasa.gov/cgi-bin/gistemp/stdata_show_v4.cgi?id=USC00054452&dt=1&ds=14

We all listen and believe what we hear…how do any of us know the true reason for global warming.

Cavemen lit fires to keep warm and cook……fossil fuels They kept Cattle/Sheep etc…………meat we are told contributes.

We are told that we will all be driving electric vehicles soon……I think this is utter rubbish, where will all the chargers be, people in high rise blocks, terrace housing.What happens when a 4 hour tailback occurs in winter and the 6 mile of traffic begin to run out of juice. Electric Cars are a Money Spinner in my opinion.

We are told that we all will be using a new type of Heating in our houses, how will people afford this?

I think we should get our priorities right and tackle things we can solve, such as ridding of plastic.

In the UK/world banning fireworks(no mention of this in UK, but surely it would be part of “Our Bit”).

Trees planting needs to be done on a very large scale

Less talking and more LOGICAL action.

I could go on and on but we all have our own opinions I suppose.

any problem ever can only be cured by fixing the Root Cause the Root Cause of the p roblem is the Planet is over populated with half of the present population on earth we would not have a worry at all but nobody wants to even discuss that for fear of beeing stoned because we need more consumers and nobody has an idea how our world could be without more of everything tomorrow and more of everything willonly bring more troubles

Yes, population and overconsumption can strain resources. But when you get down to it, climate change is caused by burning fossil fuels, not by having babies

fossil fuels Plastics clothing food and on and on and yes your point is well taken but I said the root cause ( not Having Babies) just too many is the problem in my humble opinion Fossi fuels have been burn by Humans since Day one but now we have Billions doing it and I have to admit I like burning Fossill Fuels Campfires Woodstoves and Fast Cars too look at all the wars and the Fossil fuels consumed there too many people rubbing each other the wrong way

Wood isn’t a fossil fuel.

Referring to those who are skeptical about the cause of climate change as “Climate deniers” reveals your confirmation bias. Demonizing those who have a different opinion than yours does not give your opinion much credence.

Dave , that is true ; the denigrating attitude by labeling “Climate Deniers” questions the credibility of those saying it and exposes those, that can’t logically argue or prove CO2 Warming. The next form of propaganda tactics is that Climate Change is “decided” & that 97% of ALL Scientists say it is man made..? Even if that were true,, that does NOT indicate they are referencing CO2 as the causation driver for any such change.!

The Scientific Method, apparently does not apply to the CO2 hypothesis as most jump the steps and contrive model conclusions for outcomes. Not only is CO2 a fractional gas, its radiant absorption is so minuscule that it is UNPROVEN beyond the Lab.! CO2 is unlikely to produce sufficient heat differential in the atmosphere, to be a key driver in the green house effect among the many factors. CC maybe anthropogenic ; but unlikely CO2. No one in Science should be absolute, either way.!

Today , we need CO2 to be above 400 ppm because “plant growth” is very dependent upon photosynthesis whereby CO2 is a prerequisite. Fortunately , CO2 has increased with the population and Farmers have been able to produce “greater yields” on rate of growth. It is also a fact that many regions of the world, would fail to harvest within Season, if we were back to 280 ppm today. “Life on Earth” ; depends on enough CO2.

Almost all Predictions from Professors to the IPCC, involving Warming “doom & gloom” have “failed spectacularly” to materialize only to see excuses, postponements & change of focus. The Oceans have not risen and the harbors are not flooding. Corrupted models and misinformation is standard ; whereby any disaster is a Climate Change event.Cooling is also happening globally, ( yet ignored by the IPCC ) there’s two sides to this blind sided faith. CC no longer represents the Scientific Method.

“Oceans have not risen”? Miami and Charleston flood from the tide on sunny days for a while now. Mangroves are endangered by salt water encroaching for a while now. A Virginia military base mentioned needing to re-build, because flooding airstrips wouldn’t be usable, about twenty years ago.

What about the historical timeline of the Earth. CO2 levels have been as high as 7000ppm with no human presence at all.

Why do climate scientists NEVER show the entire timeline of CO2 records?

Only showing the last 1000 or 2000 years and zooming in on the chart looks really scary, but when you zoom out to hundreds of millions of years, why is it that global temps and co2 is much much higher, but never shown or mentioned?

You’re right there were warmer periods in the far geologic past. It’s the climate stability that supports a species survival. Why did the dinosaurs collapse? A change occurred so fast they couldn’t adapt. And any life depending on their survival went with them. And now, it’s the rapid change of avg temperature that is alarming (not the temperature itself). These changes will cause disruption, lead to chaos, and potentially civilization as we know it may be in jeopardy. If you don’t mind a Mad max world, then maybe none of this will matter. Or we can prepare in some way so that we don’t resort to panic when havoc ensues.

Excuse my ignorance, if this is the warmest the oceans have been for half a century, what caused them to start cooling 49 years ago?

I’m not a scientist by any means. From what I understand we are pretty much screwed. One reason is we for some reason can’t get our heads out of our asses and see what is right in front of us…our planet is dying. We messed up. Too selfish to stop and actually fix our mistakes we just keep taking and taking. It’s a pathetic and frankly unknown legacy we leave our children.

We don’t have records that go back 4.5 billion years age of earth

      As I get older I am starting to care about nature more. I love The Native Trees Plant and Wildlife more than our Consumer Society. People are arguing on both sides of The Global Warming Issue but I think a lot of THE PROBLEM IS THAT WE ARE WASTEFUL. HOW MANY OF THE THING WE HAVE TODAY ARE REALLY NECESSARY AND DO THESE THINGS REALLY MAKE US HAPPY? HOW LONG DO WE KEEP THE THINGS WE BUY BEFORE THEY ARE THROW INTO THE GARBAGE AND END UP IN A LAND FILL? WE USE TO MUCH PLASTIC.           WE ARE ADDICTED TO POWER. DOES THIS REALLY MAKE US HAPPY? Wind Mills, Solar Panels, Nuclear Power Plants and other Alternate Energy Sources all have their negatives. People talk about planting Trees but what about not cutting down The Mature Trees in the first place. It takes a while for a tree to grow. I am not sure how much of the CO2 comes from Trees being burned and the dead Trees that are not burned but I hate seeing Trees being cut down.            The problem is People are not willing to give up our throw away Society. People want Big Houses that take a lot of energy to heat. Often they just want a Big House for as a Prestige Symbol. Mowing all The Turf Lawns that need to be mowed every week takes energy. These Lawns do not support Wild Life. Turf Lawns are considered a sign of wealth and are for just for  prestige. Leaf blowers are noisy and obnoxious. To often it is noisy where I live, Lawn Mowers, Helicopters, Leaf Blower and other Machines. I do not know how to live with out the technical society I was brought up in and live in today but I wish I had a Simpler Life and knew how to live a Simpler Life. A life  that did not destroy The Natural Native Species of Trees Plant and Animals. These things are beautiful and give life meaning. To many people are only concerned about these thing for what they can get out of them and to support human life but they do not love them. If they loved them they would not destroy them. If people do not destroy them they will support life

The science seems to be largely based on subjective intuition/opinion, so called expert judgment, and computer modelling, that is, the most complex system on earth represented in abstract lines of code, and the temperature records, whether surface or satellite, has well-known criticisms I shouldn’t have to mention to state its fair to be wary of relying on them so heavily. I was reading an article and it said expert opinion is becoming data in its own right. This is not science. Would you take a vaccine or medical treatment if the models said it worked and 99 percent of scientists said it was safe (and there were no human and animal trials)? Then why shouldn’t critical judgment and caution be placed on this propaganda dominated science, even the IPCC stated in an old report (paraphrased): this is “science for policy” a less rigorous science than traditionally practiced.

So what’s the difference between temperature increases and sea levels rising 10,000 years ago, when the global population was less than 3 million with a miniscule carbon footprint and now? For example sea levels rose tens of metres between 6000 and 10000 bc with clear examples, such as the submersion of Doggerland, that used to connect Europe to the UK.

If sea levels can rise by 30 metres in such a short timeframe with no human CO2 emissions, then why should anyone believe human CO2 emissions are now the primary cause. Surely, the focus of scientific effort to understand the reasons for climate change and whether humans impact it, should be the study of previous examples of evidenced based temp change and sea level rises and to assess whether there are direct comparisons to current conditions.

There appears to be far more evidence that climate change and sea level fluctuations have always happened irrespective of any significant CO2 changes, so it’s entirely logical and sensible to strongly challenge why current global conditions are any different now compared to any other time in history and whether CO2 really has any discernible impact, other than increased CO2 providing more favourable conditions for life to flourish

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Causes of global warming, explained

Human activity is driving climate change, including global temperature rise.

The average temperature of the Earth is rising at nearly twice the rate it was 50 years ago. This rapid warming trend cannot be explained by natural cycles alone, scientists have concluded. The only way to explain the pattern is to include the effect of greenhouse gases (GHGs) emitted by humans.

Current levels of the greenhouse gases carbon dioxide, methane, and nitrous oxide in our atmosphere are higher than at any point over the past 800,000 years , and their ability to trap heat is changing our climate in multiple ways .

IPCC conclusions

To come to a scientific conclusion on climate change and what to do about it, the United Nations in 1988 formed a group called the Intergovernmental Panel on Climate Change , or IPCC. The IPCC meets every few years to review the latest scientific findings and write a report summarizing all that is known about global warming. Each report represents a consensus, or agreement, among hundreds of leading scientists.

One of the first things the IPCC concluded is that there are several greenhouse gases responsible for warming, and humans emit them in a variety of ways. Most come from the combustion of fossil fuels in cars, buildings, factories, and power plants. The gas responsible for the most warming is carbon dioxide, or CO2. Other contributors include methane released from landfills, natural gas and petroleum industries, and agriculture (especially from the digestive systems of grazing animals); nitrous oxide from fertilizers; gases used for refrigeration and industrial processes; and the loss of forests that would otherwise store CO2.

Gaseous abilities

Different greenhouse gases have very different heat-trapping abilities. Some of them can trap more heat than an equivalent amount of CO2. A molecule of methane doesn't hang around the atmosphere as long as a molecule of carbon dioxide will, but it is at least 84 times more potent over two decades. Nitrous oxide is 264 times more powerful than CO2.

Other gases, such as chlorofluorocarbons, or CFCs—which have been banned in much of the world because they also degrade the ozone layer—have heat-trapping potential thousands of times greater than CO2. But because their emissions are much lower than CO2 , none of these gases trap as much heat in the atmosphere as CO2 does.

When those gases that humans are adding to Earth's atmosphere trap heat, it’s called the "greenhouse effect." The gases let light through but then keep much of the heat that radiates from the surface from escaping back into space, like the glass walls of a greenhouse. The more greenhouse gases in the atmosphere, the more dramatic the effect, and the more warming that happens.

Climate change continues

Despite global efforts to address climate change, including the landmark 2015 Paris climate agreement , carbon dioxide emissions from fossil fuels continue to rise, hitting record levels in 2018 .

Many people think of global warming and climate change as synonyms, but scientists prefer to use “climate change” when describing the complex shifts now affecting our planet’s weather and climate systems. Climate change encompasses not only rising average temperatures but also extreme weather events, shifting wildlife populations and and habitats, rising seas , and a range of other impacts.

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ENCYCLOPEDIC ENTRY

Global warming.

The causes, effects, and complexities of global warming are important to understand so that we can fight for the health of our planet.

Earth Science, Climatology

Tennessee Power Plant

Ash spews from a coal-fueled power plant in New Johnsonville, Tennessee, United States.

Photograph by Emory Kristof/ National Geographic

Learning materials

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Global warming is the long-term warming of the planet’s overall temperature. Though this warming trend has been going on for a long time, its pace has significantly increased in the last hundred years due to the burning of fossil fuels . As the human population has increased, so has the volume of fossil fuels burned. Fossil fuels include coal, oil, and natural gas, and burning them causes what is known as the “greenhouse effect” in Earth’s atmosphere.

The greenhouse effect is when the sun’s rays penetrate the atmosphere, but when that heat is reflected off the surface cannot escape back into space. Gases produced by the burning of fossil fuels prevent the heat from leaving the atmosphere. These greenhouse gasses are carbon dioxide , chlorofluorocarbons, water vapor , methane , and nitrous oxide . The excess heat in the atmosphere has caused the average global temperature to rise overtime, otherwise known as global warming.

Global warming has presented another issue called climate change. Sometimes these phrases are used interchangeably, however, they are different. Climate change refers to changes in weather patterns and growing seasons around the world. It also refers to sea level rise caused by the expansion of warmer seas and melting ice sheets and glaciers . Global warming causes climate change, which poses a serious threat to life on Earth in the forms of widespread flooding and extreme weather. Scientists continue to study global warming and its impact on Earth.

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Lesson of the Day

Explore 7 Climate Change Solutions

In this lesson, students will use a jigsaw activity to learn about some of the most effective strategies and technologies that can help head off the worst effects of global warming.

By Natalie Proulx

Lesson Overview

Earlier this summer, a report issued by the Intergovernmental Panel on Climate Change , a body of scientists convened by the United Nations, found that some devastating impacts of global warming were unavoidable. But there is still a short window to stop things from getting even worse.

This report will be central at COP26 , the international climate summit where about 20,000 heads of state, diplomats and activists are meeting in person this week to set new targets for cutting emissions from coal, oil and gas that are heating the planet.

In this lesson, you will learn about seven ways we can slow down climate change and head off some of its most catastrophic consequences while we still have time. Using a jigsaw activity , you’ll become an expert in one of these strategies or technologies and share what you learn with your classmates. Then, you will develop your own climate plan and consider ways you can make a difference based on your new knowledge.

What do you know about the ways the world can slow climate change? Start by making a list of strategies, technologies or policies that could help solve the climate crisis.

Which of your ideas do you think could have the biggest impact on climate change? Circle what you think might be the top three.

Now, test your knowledge by taking this 2017 interactive quiz:

How Much Do You Know About Solving Global Warming?

A new book presents 100 potential solutions. Can you figure out which ones are top ranked?

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