| Summary: | Thesis (Master's)--University of Washington, 2015 We employed a linked hydro-biogeochemical model framework to study the surface methane emissions from Pan-Arctic wetlands over the period 1948-2006. We also performed a set of climate control experiments to investigate the sensitivity of methane emissions to climate change over 1960-2006. We estimated the average methane emission from Pan-Arctic wetlands during 1960-2006 as 35.05 ± 6.66 TgCH4/year. This is slightly higher than the previous studies. The wetland methane emissions showed a significant increasing trend of 0.15TgCH4/year (p<10-5). Changes in air temperature are the cause of most of the inferred trend. At 5% significance level, over 90% of the increase in the wetland methane emissions during 1960-2006 can be attributed to climate warming. We also found that the climate sensitivity of CH4 emissions is relatively constant at the grid scale. Based on these inferred coefficients, we estimate that the Pan-Arctic wetland methane emissions will continue to increase under RCP4.5 climate scenario, and the 2100s emission would be 135% of the 2000s level.
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