Greenhouse gas emissions from wetlands

See also: Marsh gas
A heat map of the planet showing methane emissions from wetlands from 1980 to 2021

Greenhouse gas emissions from wetlands of concern consist primarily of methane and nitrous oxide emissions. Wetlands are the largest natural source of atmospheric methane in the world, and are therefore a major area of concern with respect to climate change.[1][2][3] Wetlands account for approximately 20–30% of atmospheric methane through emissions from soils and plants, and contribute an approximate average of 161 Tg of methane to the atmosphere per year.[4]

Wetlands are characterized by water-logged soils and distinctive communities of plant and animal species that have adapted to the constant presence of water. This high level of water saturation creates conditions conducive to methane production. Most methanogenesis, or methane production, occurs in oxygen-poor environments. Because the microbes that live in warm, moist environments consume oxygen more rapidly than it can diffuse in from the atmosphere, wetlands are the ideal anaerobic environments for fermentation as well as methanogen activity. However, levels of methanogenesis fluctuates due to the availability of oxygen, soil temperature, and the composition of the soil. A warmer, more anaerobic environment with soil rich in organic matter would allow for more efficient methanogenesis.[5]

Some wetlands are a significant source of methane emissions[6][7] and some are also emitters of nitrous oxide.[8][9] Nitrous oxide is a greenhouse gas with a global warming potential 300 times that of carbon dioxide and is the dominant ozone-depleting substance emitted in the 21st century.[10] Wetlands can also act as a sink for greenhouse gases.[11]

  1. ^ Houghton, J. T., et al. (Eds.) (2001) Projections of future climate change, Climate Change 2001: The Scientific Basis, Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change, 881 pp.
  2. ^ Comyn-Platt, Edward (2018). "Carbon budgets for 1.5 and 2 °C targets lowered by natural wetland and permafrost feedbacks" (PDF). Nature. 11 (8): 568–573. Bibcode:2018NatGe..11..568C. doi:10.1038/s41561-018-0174-9. S2CID 134078252.
  3. ^ Bridgham, Scott D.; Cadillo-Quiroz, Hinsby; Keller, Jason K.; Zhuang, Qianlai (May 2013). "Methane emissions from wetlands: biogeochemical, microbial, and modeling perspectives from local to global scales". Global Change Biology. 19 (5): 1325–1346. Bibcode:2013GCBio..19.1325B. doi:10.1111/gcb.12131. PMID 23505021. S2CID 14228726.
  4. ^ Saunois, Marielle; Stavert, Ann R.; Poulter, Ben; Bousquet, Philippe; Canadell, Josep G.; Jackson, Robert B.; Raymond, Peter A.; Dlugokencky, Edward J.; Houweling, Sander; Patra, Prabir K.; Ciais, Philippe; Arora, Vivek K.; Bastviken, David; Bergamaschi, Peter; Blake, Donald R. (2020-07-15). "The Global Methane Budget 2000–2017". Earth System Science Data. 12 (3): 1561–1623. doi:10.5194/essd-12-1561-2020. hdl:1721.1/124698. ISSN 1866-3508.
  5. ^ Christensen, T. R., A. Ekberg, L. Strom, M. Mastepanov, N. Panikov, M. Oquist, B. H. Svenson, H. Nykanen, P. J. Martikainen, and H. Oskarsson (2003), Factors controlling large scale variations in methane emissions from wetlands, Geophys. Res. Lett., 30, 1414, doi:10.1029/2002GL016848.
  6. ^ Masso, Luana S.; Marani, Luciano; Gatti, Luciana V.; Miller, John B.; Gloor, Manuel; Melack, John; Cassol, Henrique L. G.; Tejada, Graciela; Domingues, Lucas G.; Arai, Egidio; Sanchez, Alber H.; Corrêa, Sergio M.; Anderson, Liana; Aragão, Luiz E. O. C.; Correa, Caio S. C.; Crispim, Stephane P.; Neves, Raiane A. L. (29 November 2021). "Amazon methane budget derived from multi-year airborne observations highlights regional variations in emissions". Communications Earth & Environment. 2 (1): 246. Bibcode:2021ComEE...2..246B. doi:10.1038/s43247-021-00314-4. S2CID 244711959.
  7. ^ Tiwari, Shashank; Singh, Chhatarpal; Singh, Jay Shankar (2020). "Wetlands: A Major Natural Source Responsible for Methane Emission". In Upadhyay, Atul Kumar; Singh, Ranjan; Singh, D. P. (eds.). Restoration of Wetland Ecosystem: A Trajectory Towards a Sustainable Environment. Singapore: Springer. pp. 59–74. doi:10.1007/978-981-13-7665-8_5. ISBN 978-981-13-7665-8. S2CID 198421761.
  8. ^ Bange, Hermann W. (2006). "Nitrous oxide and methane in European coastal waters". Estuarine, Coastal and Shelf Science. 70 (3): 361–374. Bibcode:2006ECSS...70..361B. doi:10.1016/j.ecss.2006.05.042.
  9. ^ Thompson, A. J.; Giannopoulos, G.; Pretty, J.; Baggs, E. M.; Richardson, D. J. (2012). "Biological sources and sinks of nitrous oxide and strategies to mitigate emissions". Philosophical Transactions of the Royal Society B. 367 (1593): 1157–1168. doi:10.1098/rstb.2011.0415. PMC 3306631. PMID 22451101.
  10. ^ Ravishankara, A. R.; Daniel, John S.; Portmann, Robert W. (2009). "Nitrous Oxide (N2O): The Dominant Ozone-Depleting Substance Emitted in the 21st Century". Science. 326 (5949): 123–125. Bibcode:2009Sci...326..123R. doi:10.1126/science.1176985. PMID 19713491. S2CID 2100618.
  11. ^ Sonwani, Saurabh; Saxena, Pallavi (2022-01-21). Greenhouse Gases: Sources, Sinks and Mitigation. Springer Nature. pp. 47–48. ISBN 978-981-16-4482-5.