MethaneMIP

Learn about methane

What you need to know about methane

Methane (CH4) is a potent greenhouse gas with an atmospheric lifetime much shorter than carbon dioxide (CO2). Methane emissions have contributed substantially to observed climate change over the past 150 years. Methane also has implications for the climate system, human health, air pollution and agriculture.

Methane emissions have been the second most important cause of climate change behind CO2

The Intergovernmental Panel on Climate Change Sixth Assessment Report estimates that of the total 1.1 °C of warming in 2010 to 2019 relative to 1850 to 1900, approximately 0.5 °C is attributable to increased methane emissions. Since the pre-industrial period, atmospheric methane concentrations have nearly tripled, and it is well established that this increase has been driven by human activity (Jackson et al., 2020; UNEP and CCAC, 2021; Skeie et al., 2023).

Methane is an extremely potent greenhouse gas, sometimes labeled a super-pollutant

On a molecule by molecule basis, methane is a much more potent greenhouse gas than carbon dioxide, with an estimated 81 to 83 times larger 20 year global warming potential and 27 to 30 times larger 100 year global warming potential (Forster et al., 2021). Methane nonetheless makes up a much smaller fraction of atmospheric concentrations, and of anthropogenic emissions, than carbon dioxide.

Methane is designated as a short-lived climate forcing agent

Methane has an atmospheric lifetime of approximately a decade (Szopa et al., 2021), much shorter than that of carbon dioxide. This is because methane is more chemically reactive in the atmosphere and is removed through faster processes. As a consequence, reductions in methane emissions are expected to slow the rate of global warming within a decade (UNEP and CCAC, 2021; Ocko et al., 2021).

Methane is a key contributor to the formation of ground-level ozone, a dangerous air pollutant

The UNEP 2021 Global Methane Assessment estimates that ozone attributable to anthropogenic methane emissions causes approximately half a million premature deaths per year globally, and harms ecosystems and crops by suppressing growth and reducing yields.

Ozone exposure increases mortality primarily through effects on the respiratory and cardiovascular systems. Including the health impacts of methane related ozone would more than double the social cost of methane currently used by the US government (McDuffie et al., 2023).

Methane has further implications for climate beyond its direct radiative effect

Through its chemical effects in the atmosphere, methane leads to increased concentrations of carbon dioxide, water vapor and ozone, both stratospheric and tropospheric, all of which are themselves greenhouse gases. This can increase the radiative forcing attributed to methane by more than 50% (Szopa et al., 2021).

Through its effects on stratospheric water vapor and stratospheric ozone, methane also has an important role in stratospheric climate. The fingerprint of methane on the atmospheric circulation and on regional climate is less clear than that of carbon dioxide, as it is much less studied.

According to ice core data, modern atmospheric methane concentrations are higher than at any time over the past 800,000 years (Canadell et al., 2021). Over the past decade, concentrations have surged to new record highs (Lan et al., 2025). The precise drivers of the plateau in methane levels in the early 2000s, and of the recent rise, are areas of active research (Turner et al., 2019; Oh et al., 2022; Qu et al., 2022).

References

  • Canadell, J. G., Monteiro, P. M. S., Costa, M. H., Cotrim da Cunha, L., Cox, P. M., Eliseev, A. V., Henson, S., Ishii, M., Jaccard, S., Koven, C., Lohila, A., Patra, P. K., Piao, S., Rogelj, J., Syampungani, S., Zaehle, S., and Zickfeld, K.: Global Carbon and other Biogeochemical Cycles and Feedbacks, pp. 673–816, in Climate Change 2021: The Physical Science Basis, Cambridge University Press, 2021.
  • Forster, P., Storelvmo, T., Armour, K., Collins, W., Dufresne, J., Frame, D., Lunt, D., Mauritsen, T., Palmer, M., Watanabe, M., Wild, M., and Zhang, H.: The Earth's Energy Budget, Climate Feedbacks, and Climate Sensitivity, pp. 923–1054, in Climate Change 2021: The Physical Science Basis, Cambridge University Press, 2021.
  • IPCC: Summary for Policymakers, pp. 3–32, in Masson-Delmotte, V., Zhai, P., Pirani, A., Connors, S., Péan, C., Berger, S., Caud, N., Chen, Y., Goldfarb, L., Gomis, M., Huang, M., Leitzell, K., Lonnoy, E., Matthews, J., Maycock, T., Waterfield, T., Yelekçi, O., Yu, R., and Zhou, B. (eds.), Climate Change 2021: The Physical Science Basis, Cambridge University Press, 2021.
  • Jackson, R. B., Saunois, M., Bousquet, P., Canadell, J. G., Poulter, B., Stavert, A. R., Bergamaschi, P., Niwa, Y., Segers, A., and Tsuruta, A.: Increasing anthropogenic methane emissions arise equally from agricultural and fossil fuel sources, Environmental Research Letters, 15, 071002, doi:10.1088/1748-9326/ab9ed2, 2020.
  • Lan, X., Thoning, K. W., and Dlugokencky, E. J.: Trends in globally averaged CH4, N2O and SF6 determined from NOAA Global Monitoring Laboratory measurements, Version 2025-02, doi:10.15138/P8XG-AA10.
  • McDuffie, E. E., Sarofim, M. C., Raich, W., Jackson, M., Roman, H., Seltzer, K., Henderson, B. H., Shindell, D. T., Collins, M., Anderton, J., Barr, S., and Fann, N.: The Social Cost of Ozone-Related Mortality Impacts From Methane Emissions, Earth's Future, 11, doi:10.1029/2023EF003853, 2023.
  • Ocko, I. B., Sun, T., Shindell, D., Oppenheimer, M., Hristov, A. N., Pacala, S. W., Mauzerall, D. L., Xu, Y., and Hamburg, S. P.: Acting rapidly to deploy readily available methane mitigation measures by sector can immediately slow global warming, Environmental Research Letters, 16, 054042, doi:10.1088/1748-9326/abf9c8, 2021.
  • Oh, Y., Zhuang, Q., Welp, L. R., Liu, L., Lan, X., Basu, S., Dlugokencky, E. J., Bruhwiler, L., Miller, J. B., Michel, S., Schwietzke, S., Tans, P. P., Ciais, P., and Chanton, J. P.: Improved global wetland carbon isotopic signatures support post-2006 microbial methane emission increase, Communications Earth and Environment, 3, doi:10.1038/s43247-022-00488-5, 2022.
  • Qu, Z., Jacob, D., Zhang, Y., Shen, L., Varon, D. J., Lu, X., Scarpelli, T. R., Bloom, A. A., Worden, J., and Parker, R. J.: Attribution of the 2020 surge in atmospheric methane by inverse analysis of GOSAT observations, Environmental Research Letters, 17, 094003, doi:10.1088/1748-9326/ac8754, 2022.
  • Skeie, R. B., Hodnebrog, Ø., and Myhre, G.: Trends in atmospheric methane concentrations since 1990 were driven and modified by anthropogenic emissions, Communications Earth and Environment, 4, doi:10.1038/s43247-023-00969-1, 2023.
  • Szopa, S., Naik, V., Adhikary, B., Artaxo, P., Berntsen, T., Collins, W., Fuzzi, S., Gallardo, L., Kiendler-Scharr, A., Klimont, Z., Liao, H., Unger, N., and Zanis, P.: Short-Lived Climate Forcers, pp. 817–922, in Climate Change 2021: The Physical Science Basis, Cambridge University Press, 2021.
  • Turner, A. J., Frankenberg, C., and Kort, E. A.: Interpreting contemporary trends in atmospheric methane, Proceedings of the National Academy of Sciences, 116, 2805–2813, doi:10.1073/pnas.1814297116, 2019.
  • UNEP and CCAC: Global Methane Assessment: Benefits and Costs of Mitigating Methane Emissions, United Nations Environment Programme, 2021.