Quantifying Future Changes in High-Latitude Methane Emissions Under Regional Climate Change Uncertainty

The arctic is a highly sensitive region to be profoundly affected by global warming and would likely experience greater warming than the rest of the world. One immediate consequence of climate change in the Arctic would likely be the widespread permafrost degradation and thus a strong increase in methane emission (via thermokarst lakes and /or wetland expansion). In this study, we attempt to quantify the future changes in the high latitude methane emission by forcing the community land model (CLM) with the climate projections from the fully-coupled MIT Integrated Global System Model (IGSM) simulations of low, median and high climate sensitivity through the next century (2100). In order to take into account the regional uncertainty in climate change, the GPCP precipitation and CRU temperature are employed to project the zonal-based IGSM forcing data into the longitudinally gridded domain. The feasibility of such zonal-to-longitude projection will be validated with the offline CLM simulations forced by three other state-of-the-art meteorology datasets. Additional simulations will be performed through the 2100 to examine the impact of warming climate on the zonal-to-longitude projection coefficients and associated methane emission by imposing two distinct GCM patterns (warm and dry / cool and wet) from IPCC AR4 archive on the MIT IGSM climate projections. The research results from this study should help us better understand the change and future states of the high latitude methane emission and also provide useful insights on the potential climate feedback.