This article is a contribution of the Methane Working Group of the National Center for Ecological Analysis and Synthesis, University of California, Santa Barbara. The research is also supported by U.S. National Science Foundation grants ARC-0554811 and EAR-0630319 to Q. Zhuang and by NASA’s Large-Scale Biosphere-Atmosphere Experiment in Amazonia program.
EOS, Transactions American Geophysical Union
Air -- Pollution, Methane -- Measurement, Methane -- Environmental aspects
The current concentration of atmospheric methane is 1774±1.8 parts per billion, and it accounts for 18% of total greenhouse gas radiative forcing [Forster et al., 2007]. Atmospheric methane is 22 times more effective, on a per-unit-mass basis, than carbon dioxide in absorbing long-wave radiation on a 100-year time horizon, and it plays an important role in atmospheric ozone chemistry (e.g., in the presence of nitrous oxides, tropospheric methane oxidation will lead to the formation of ozone). Wetlands are a large source of atmospheric methane, Arctic lakes have recently been recognized as a major source [e.g., Walter et al., 2006], and anthropogenic activities--such as rice agriculture--also make a considerable contribution.
Zhuang, Q., J. M. Melack, S. Zimov, K. M. Walter, C. L. Butenhoff, and M. A. K. Khalil (2009), Global Methan Emissions From Wetlands, Rice Paddies, and Lakes, Eos Trans. AGU, 90(5), 37, doi:10.1029/2009EO050001.