Greenhouse gas

This article is about the physical properties of greenhouse gases. For how human activities are adding to greenhouse gases, see Greenhouse gas emissions.
Greenhouse gases trap some of the heat that results when sunlight heats the Earth's surface. Three important greenhouse gases are shown symbolically in this image: carbon dioxide, water vapor, and methane.
Physical drivers of global warming that has happened so far. Future global warming potential for long lived drivers like carbon dioxide emissions is not represented. Whiskers on each bar show the possible error range.

Greenhouse gases (GHGs) are the gases in the atmosphere that raise the surface temperature of planets such as the Earth. What distinguishes them from other gases is that they absorb the wavelengths of radiation that a planet emits, resulting in the greenhouse effect.[1] The Earth is warmed by sunlight, causing its surface to radiate heat, which is then mostly absorbed by greenhouse gases. Without greenhouse gases in the atmosphere, the average temperature of Earth's surface would be about −18 °C (0 °F),[2] rather than the present average of 15 °C (59 °F).[3][4]

The five most abundant greenhouse gases in Earth's atmosphere, listed in decreasing order of average global mole fraction, are:[5][6] water vapor, carbon dioxide, methane, nitrous oxide, ozone. Other greenhouse gases of concern include chlorofluorocarbons (CFCs and HCFCs), hydrofluorocarbons (HFCs), perfluorocarbons, SF
6, and NF
3. Water vapor causes about half of the greenhouse effect, acting in response to other gases as a climate change feedback.[7]

Human activities since the beginning of the Industrial Revolution (around 1750) have increased carbon dioxide by over 50%,[8] and methane levels by 150%.[9] Carbon dioxide emissions are causing about three-quarters of global warming, while methane emissions cause most of the rest.[10] The vast majority of carbon dioxide emissions by humans come from the burning of fossil fuels,[11] with remaining contributions from agriculture and industry.[12]: 687  Methane emissions originate from agriculture, fossil fuel production, waste, and other sources.[13] The carbon cycle takes thousands of years to fully absorb CO2 from the atmosphere,[14] while methane lasts in the atmosphere for an average of only 12 years.[15]

Natural flows of carbon happen between the atmosphere, terrestrial ecosystems, the ocean, and sediments. These flows have been fairly balanced over the past 1 million years,[16] although greenhouse gas levels have varied widely in the more distant past. Carbon dioxide levels are now higher than they have been for 3 million years.[17] If current emission rates continue then global warming will surpass 2.0 °C (3.6 °F) sometime between 2040 and 2070. This is a level which the Intergovernmental Panel on Climate Change (IPCC) says is "dangerous".[18]

  1. ^ Matthews, J.B.R.; Möller, V.; van Diemenn, R.; Fuglesvedt, J.R.; et al. (9 August 2021). "Annex VII: Glossary". In Masson-Delmotte, Valérie; Zhai, Panmao; Pirani, Anna; Connors, Sarah L.; Péan, Clotilde; et al. (eds.). Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (PDF). IPCC / Cambridge University Press. pp. 2215–2256. doi:10.1017/9781009157896.022. ISBN 9781009157896.
  2. ^ Cite error: The named reference NASACO2 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Trenberth2003 was invoked but never defined (see the help page).
  4. ^ Le Treut, H., R. Somerville, U. Cubasch, Y. Ding, C. Mauritzen, A. Mokssit, T. Peterson and M. Prather, 2007: "Chapter 1: Historical Overview of Climate Change". In: "Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change". [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
  5. ^ "Atmospheric Concentration of Greenhouse Gases" (PDF). U.S. Environmental Protection Agency. 1 August 2016. Archived (PDF) from the original on 19 October 2021. Retrieved 6 September 2021.
  6. ^ "Inside the Earth's invisible blanket". sequestration.org. Archived from the original on 28 July 2020. Retrieved 5 March 2021.
  7. ^ Gavin Schmidt (1 October 2010). "Taking the Measure of the Greenhouse Effect". NASA Goddard Institute for Space Studies – Science Briefs.
  8. ^ "Carbon dioxide now more than 50% higher than pre-industrial levels". National Oceanic and Atmospheric Administration. 3 June 2022. Retrieved 30 August 2022.
  9. ^ "Understanding methane emissions". International Energy Agency. The concentration of methane in the atmosphere is currently over two-and-a-half times greater than its pre-industrial levels
  10. ^ "Global Greenhouse Gas Emissions Data". United States Environmental Protection Agency. 12 January 2016.
  11. ^ "Global Greenhouse Gas Emissions Data". U.S. Environmental Protection Agency. 12 January 2016. Archived from the original on 5 December 2019. Retrieved 30 December 2019. The burning of coal, natural gas, and oil for electricity and heat is the largest single source of global greenhouse gas emissions.
  12. ^ Canadell, J.G., P.M.S. Monteiro, M.H. Costa, L. Cotrim da Cunha, P.M. Cox, A.V. Eliseev, S. Henson, M. Ishii, S. Jaccard, C. Koven, A. Lohila, P.K. Patra, S. Piao, J. Rogelj, S. Syampungani, S. Zaehle, and K. Zickfeld, 2021: Chapter 5: Global Carbon and other Biogeochemical Cycles and Feedbacks. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 673–816, doi:10.1017/9781009157896.007.
  13. ^ "Global Methane Tracker 2023". International Energy Agency. 21 February 2023.
  14. ^ "Climate Change Indicators: Greenhouse Gases". United States Environmental Protection Agency. 16 December 2015. Carbon dioxide's lifetime cannot be represented with a single value because the gas is not destroyed over time, but instead moves among different parts of the ocean–atmosphere–land system. Some of the excess carbon dioxide is absorbed quickly (for example, by the ocean surface), but some will remain in the atmosphere for thousands of years, due in part to the very slow process by which carbon is transferred to ocean sediments.
  15. ^ "Understanding methane emissions". International Energy Agency.
  16. ^ "Climate Change Indicators: Atmospheric Concentrations of Greenhouse Gases". EPA.gov. U.S. Environmental Protection Agency. 27 June 2016. Retrieved 20 June 2024.
  17. ^ Lindsey, Rebecca. "Climate Change: Atmospheric Carbon Dioxide". climate.gov. Archived from the original on 24 June 2013. Retrieved 2 March 2020.
  18. ^ "Analysis: When might the world exceed 1.5C and 2C of global warming?". Carbon Brief. 4 December 2020. Archived from the original on 6 June 2021. Retrieved 17 June 2021.