THE EFFECTS OF CLIMATE-CHANGE ON LAND ATMOSPHERE FEEDBACKS IN ARCTIC TUNDRA REGIONS

Recently reported high-latitude warming has the potential to affect arctic ecosystem structure and function in the short and long term. Arctic ecosystems are known sources of atmospheric CH4, and recent CO2 flux measurements indicate that these ecosystems are now, at least regionally, net sources of atmospheric CO2. It appears that over the short term (decades to centuries), arctic ecosystems may represent a positive feedback on global atmospheric CO2 concentrations and associated greenhouse gas-induced climate change. In addition, short-term feedbacks may be large enough to affect both local and global surface temperatures. Over the long term, changes in the structure, function and composition of arctic ecosystems may increase C accumulation relatively more than the amount lost, thus restoring the sink status of arctic ecosystems.