Methane Emission in the Russian Permafrost Zone and Evaluation of Its Impact on Global Climate

Abstract

Satellite data on methane concentration in the lower troposphere and the dynamical permafrost model are used to analyze methane emissions in the permafrost zone. The sources of methane generation in different biochemical conditions in the river valleys, thermokarst lakes, wetlands, and lowlands are studied. The statistical relationships between their intensity and air temperature, precipitation, active layer thickness, and permafrost temperature are evaluated. The CMIP5 ensemble climate projection is used to estimate methane emission in the permafrost regions for the mid-21st century. Numerical experiments with the INM-CM48 Earth system model demonstrated that the projected 20 Tg/year increase in the methane emission will lead to less than 0.05°C global temperature rise. The uncertainty analysis of the results is accomplished and an alternative conceptual model of abrupt threshold changes in methane emission is proposed.