期刊
ENVIRONMENTAL RESEARCH LETTERS
卷 8, 期 4, 页码 -出版社
IOP Publishing Ltd
DOI: 10.1088/1748-9326/8/4/045003
关键词
methane; carbon dioxide; greenhouse gases; climate change; Arctic; terrestrial ecosystem model; variable infiltration capacity
资金
- DOE SciDAC project
- Abrupt Climate Change project
- NASA Land Use and Land Cover Change program [NASA-NNX09AI26G]
- Department of Energy [DE-FG02-08ER64599]
- NSF Division of Information and Intelligent Systems [NSF-1028291]
- NSF Carbon and Water in the Earth Program [NSF-0630319]
- Office of Science, Office of Biological and Environmental Research of the US Department of Energy [DE-AC02-05CH11231]
- Direct For Biological Sciences
- Division Of Environmental Biology [0919331] Funding Source: National Science Foundation
Future changes of pan-Arctic land-atmospheric methane (CH4) and carbon dioxide (CO2) depend on how terrestrial ecosystems respond to warming climate. Here, we used a coupled hydrology-biogeochemistry model to make our estimates of these carbon exchanges with two contrasting climate change scenarios (no-policy versus policy) over the 21st century, by considering (1) a detailed water table dynamics and (2) a permafrost-thawing effect. Our simulations indicate that, under present climate conditions, pan-Arctic terrestrial ecosystems act as a net greenhouse gas (GHG) sink of -0.2 Pg CO2-eq.yr(-1), as a result of a CH4 source (53 Tg CH4 yr(-1)) and a CO2 sink (-0.4 Pg C yr(-1)). In response to warming climate, both CH4 emissions and CO2 uptakes are projected to increase over the century, but the increasing rates largely depend on the climate change scenario. Under the non-policy scenario, the CH4 source and CO2 sink are projected to increase by 60% and 75% by 2100, respectively, while the GHG sink does not show a significant trend. Thawing permafrost has a small effect on GHG sink under the policy scenario; however, under the no-policy scenario, about two thirds of the accumulated GHG sink over the 21st century has been offset by the carbon losses as CH4 and CO2 from thawing permafrost. Over the century, nearly all CO2-induced GHG sink through photosynthesis has been undone by CH4-induced GHG source. This study indicates that increasing active layer depth significantly affects soil carbon decomposition in response to future climate change. The methane emissions considering more detailed water table dynamics continuously play an important role in affecting regional radiative forcing in the pan-Arctic.
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