A Process-based Analysis of Methane Exchanges Between Alaskan Terrestrial Ecosystems and the Atmosphere

in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).
We developed and used a new version of the Terrestrial Ecosystem Model (TEM) to study how rates of methane (CH4) emissions and consumption in Alaskan soils have changed over the past century in response to observed changes in the state’s climate and are likely to change with projected climate changes over this century. We estimate that the current net emissions of CH4 (emissions minus consumption) from Alaskan soils are about 3 Tg CH4 per year. We project that net CH4 emissions will almost double by the end of the century in response to high-latitude warming and associated climate changes. If CH4 emissions from soils of the pan-Arctic region respond to climate changes in the way we project for the Alaskan soils, the net increase in high latitude CH4 emissions could lead to a major positive feedback to the climate system.
This work was supported by a NSF biocomplexity grant (ATM-0120468) and by the NASA Land Cover and Land Use Change Program (NAG5-6257).