Wetlands and Global Climate Change

Methane (CH ) and nitrous oxide (N2O) are two important atmospheric components that contribute to global warming, besides carbon dioxide which is the major contributor. Both methane and nitrous oxide absorb infrared radiation, while nitrous oxide is photochemically oxidized to nitric oxide (NO) resulting in ozone depletion in the stratosphere. The nitric oxide formed also governs the concentration of other greenhouse gases. The amount of nitrous oxide and methane in the atmosphere has been continuously increasing since industrialization, with current increase rates of 0.25 and 1.2% per year, respectively. 

Atmospheric lifetime (years) Global warming potential 5-200 12 114 

The methane GWPs include an indirect contribution from stratospheric H2 and O3 production. 

Wetlands, including tropical and subtropical irrigated rice, have soil conditions suitable for both methane and nitrous oxide formation and, as a result, are major anthropogenic sources of atmospheric methane and nitrous oxide. Aerobic and anaerobic enviromnents existing in wetland soil-plant systems provide conditions for both production and consumption of methane and nitrous 

Many physical, chemical, and biological factors of soil influence the production and emission of nitrous oxide and methane. Wetland hydrology and hydroperiod determine whether soil aerobic or anaerobic conditions exist. Redox status is a quantifiable measurement of the reduction process occurring in wetlands. It is well known that nitrous oxide is mainly produced through denitrification and nitrification at moderately reducing conditions, but methanogenesis occurs only under strictly anaerobic conditions. 

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Wieder R. K. and Yavitt J. B. (1994) Peatlands and global climate change insights from comparative studies of sites situated along a latitudinal gradient. Wetlands 14, 229-238. 

Cao MK, Gregson K, Marshall S. 1998. Global methane emission from wetlands and its sensitivity to climate change. Atmospheric Environment 32 3293-3299. 

Wetlands are important components of the landscape (6% of the total land surface) and exert significant influence over global carbon budgets and climate change. Wetlands contain approximately... 

Role of wetlands in regulating global elemental cycles including eutrophication, carbon sequestration, and regulation of greenhouse gases and climate change. 

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