Model estimates of climate controls on pan-Arctic wetland methane emissions
Climate factors including soil temperature and moisture, incident solar radiation, and atmospheric carbon dioxide concentration are important environmental controls on methane (CH<sub>4</sub>) emissions from northern wetlands. We investigated the spatiotemporal distributions of the influ...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-11-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/12/6259/2015/bg-12-6259-2015.pdf |
| Summary: | Climate factors including soil temperature and moisture, incident solar
radiation, and atmospheric carbon dioxide concentration are important
environmental controls on methane (CH<sub>4</sub>) emissions from northern
wetlands. We investigated the spatiotemporal distributions of the influence
of these factors on northern high-latitude wetland CH<sub>4</sub> emissions using
an enhanced version of the Variable Infiltration Capacity (VIC) land surface
model. We simulated CH<sub>4</sub> emissions from wetlands across the pan-Arctic
domain over the period 1948–2006, yielding annual average emissions of
36.1 ± 6.7 Tg CH<sub>4</sub> yr<sup>−1</sup> for the period 1997–2006. We
characterized historical sensitivities of CH<sub>4</sub> emissions to air
temperature, precipitation, incident long- and shortwave radiation, and
atmospheric [CO<sub>2</sub>] 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 CH<sub>4</sub> emissions increased by 20 %, the
majority of which can be attributed to an increasing trend in summer air
temperature. We estimated future emissions in response to 21st century
warming as predicted by CMIP5 (Coupled Model Intercomparison Project Phase 5) model projections to result in end-of-century
CH<sub>4</sub> emissions 38–53 % higher than our reconstructed 1997–2006
emissions, accompanied by the northward migration of warmer and drier than
optimal conditions for CH<sub>4</sub> emissions, implying a reduced role for
temperature in driving future increases in emissions. |
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| ISSN: | 1726-4170 1726-4189 |