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NET EMISSIONS OF CH 4 AND CO 2 IN ALASKA: IMPLICATIONS FOR THE REGION'S GREENHOUSE GAS BUDGET
Author(s) -
Zhuang Q.,
Melillo J. M.,
McGuire A. D.,
Kicklighter D. W.,
Prinn R. G.,
Steudler P. A.,
Felzer B. S.,
Hu S.
Publication year - 2007
Publication title -
ecological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.864
H-Index - 213
eISSN - 1939-5582
pISSN - 1051-0761
DOI - 10.1890/1051-0761(2007)017[0203:neocac]2.0.co;2
Subject(s) - tundra , environmental science , greenhouse gas , boreal , taiga , ecosystem , soil water , methane , terrestrial ecosystem , carbon dioxide , atmospheric sciences , climate change , context (archaeology) , ecology , soil science , geography , geology , archaeology , biology
We used a biogeochemistry model, the Terrestrial Ecosystem Model (TEM), to study the net methane (CH 4 ) fluxes between Alaskan ecosystems and the atmosphere. We estimated that the current net emissions of CH 4 (emissions minus consumption) from Alaskan soils are 3 Tg CH 4 /yr. Wet tundra ecosystems are responsible for 75% of the region's net emissions, while dry tundra and upland boreal forests are responsible for 50% and 45% of total consumption over the region, respectively. In response to climate change over the 21st century, our simulations indicated that CH 4 emissions from wet soils would be enhanced more than consumption by dry soils of tundra and boreal forests. As a consequence, we projected that net CH 4 emissions will almost double by the end of the century in response to high‐latitude warming and associated climate changes. When we placed these CH 4 emissions in the context of the projected carbon budget (carbon dioxide [CO 2 ] and CH 4 ) for Alaska at the end of the 21st century, we estimated that Alaska will be a net source of greenhouse gases to the atmosphere of 69 Tg CO 2 equivalents/yr, that is, a balance between net methane emissions of 131 Tg CO 2 equivalents/yr and carbon sequestration of 17 Tg C/yr (62 Tg CO 2 equivalents/yr).