Variable effects of climate change on carbon balance in northern ecosystems

[摘要] Accumulation of carbon dioxide (CO2) and methane (CH4) in the atmosphere of the planet accelerates climate change, and northern high-latitude regions are warming faster than the planetary average. This accelerated warming of northern regions is associated with multiple climate feedbacks, including those linked to the mobilization of old organic carbon previously sequestered in the frozen ground. This critical climate-feedback mechanism has major uncertainties, and may respond nonlinearly to ongoing warming at high latitudes. This study examines the role of freshwater ecosystems in the subarctic carbon balance, and addresses some sources of nonlinearity in the effect of climate warming on these ecosystems. Specifically, I examine the CO2 and CH4 dynamics in permafrost thaw-related ecosystems, and the associated biogeochemical processes. Our results show that major sources of variation in the dynamics of these two gases are associated with the geomorphological properties of the landscape, the degree of ground warming and seasonal biogeochemical dynamics. Accelerated climate change in northern regions may also intensify the CO2 and CH4 cycles in these regions, and may substantially increase the current CH4 flux from these ecosystems.

[发布机构] Loyola Sustainability Research Centre (LSRC), Department of Geography, Concordia University, 1455 de Maisonneuve Blvd., Montreal; QC; H3G 1M8, Canada^1;Centre for Northern Studies (CEN) and Biology Department, Laval University, 1045 Av. de la Médecine, Quebec; QC; G1V 0A6, Canada^2

[学科分类] 环境科学（综合）

[关键词] Biogeochemical dynamics;Biogeochemical process;Climate feedbacks;Freshwater ecosystem;High-latitude regions;Northern regions;Permafrost thaws;Sources of variation