TITLE

Model estimates of climate controls on pan-Arctic wetland methane emissions

AUTHOR(S)
Chen, X.; Bohn, T. J.; Lettenmaier, D. P.
PUB. DATE
April 2015
SOURCE
Biogeosciences Discussions;2015, Vol. 12 Issue 8, p5941
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Climate factors including soil temperature and moisture, incident solar radiation, and atmospheric carbon dioxide concentration are important environmental controls on methane (CH4) emissions from northern wetlands. We investigated the spatiotemporal distributions of the influence of these factors on northern high latitude wetland CH4 emissions using an enhanced version of the Variable Infiltration Capacity (VIC) land surface model. We simulated CH4 emissions from wetlands across the pan-Arctic domain over the period 1948-2006, yielding annual average emissions of 35.1 ± 6.7 TgCH4 yr-1 for the period 1997-2006. We characterized historical sensitivities to air temperature, precipitation, incident long- and short-wave radiation, and atmospheric [CO2] as a function of average summer air temperature and precipitation. Emissions from relatively warm and dry wetlands in the southern (permafrost-free) portion of the domain were positively correlated with precipitation and negatively correlated with air temperature, while emissions from wetter and colder wetlands further north (permafrost) were positively correlated with air temperature. Over the entire period 1948-2006, our reconstructed CH4 emissions increased by 20 %, over 90% of which can be attributed to climate change. An increasing trend in summer air temperature explained the majority of the climate-related variance. We estimated future emissions in response to 21st century warming as predicted by CMIP5 model projections to result in end of century CH4 emissions 42% higher than our reconstructed 1997-2006 emissions, accompanied by the northward migration of warmer- and drier-than optimal conditions for CH4 emissions, implying a reduced role for temperature in driving future increases in emissions.
ACCESSION #
102491589

 

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