The effects of climate charge 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 CH(4), and recent CO(2) flux measurements indicate that these ecosystems are now, at least regionally, net sources of atmospheric Co(2). It appears that over the short term (decades to centuries), arctic ecosystems may represent a positive feedback on global atmospheric CO(2) 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.