Rising methane emissions in response to climate change in Northern Eurasia during the 21st century, Environ

• Main Authors: Xudong Zhu, Qianlai Zhuang, Min Chen, Andrey Sirin, Jerry Melillo, David Kicklighter, Andrei Sokolov, Lulu Song
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Tundra
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1052.7809; http://www.eaps.purdue.edu/ebdl/pdfs/2011-pub-7.pdf

Abstract We used a biogeochemistry model, the Terrestrial Ecosystem Model (TEM), to examine the methane (CH 4 ) exchanges between terrestrial ecosystems and the atmosphere in Northern Eurasia from 1971 to 2100. Multiple model simulations using various wetland extent datasets and climate change scenarios were conducted to assess the uncertainty of CH 4 fluxes, including emissions and consumption. On the basis of these simulations we estimate the current net emissions in the region to be 20-24 Tg CH 4 yr −1 (1 Tg = 10 12 g), two-thirds of which are emitted during the summer. In response to climate change over the 21st century, the annual CH 4 emissions in the region are projected to increase at a rate of 0.06 Tg CH 4 yr −1 , which is an order of magnitude greater than that of annual CH 4 consumption. Further, the annual net CH 4 emissions are projected to increase by 6-51% under various wetland extent datasets and climate scenarios by the end of the 21st century, relative to present conditions. Spatial patterns of net CH 4 emissions were determined by wetland extent. Net CH 4 emissions were dominated by wetlands within boreal forests, grasslands and wet tundra areas in the region. Correlation analyses indicated that water table depth and soil temperature were the two most important environmental controls on both CH 4 emissions and consumption in the region. Our uncertainty analyses indicated that the uncertainty in wetland extent had a larger effect on future CH 4 emissions than the uncertainty in future climate. This study suggests that better characterization of the spatial distribution and the natural diversity of wetlands should be a research priority for quantifying CH 4 fluxes in this region.