Arctic carbon cycle: Patterns, impacts and possible changes

Abstract

Land and ocean uptake and release of carbon dioxide and methane play important roles for regulating their atmospheric concentrations. For example, over the industrialised period the terrestrial biosphere and global oceans have acted as net sinks of carbon dioxide, having absorbed CO2 corresponding to more than 50% of the accumulated emissions from fossil fuel burning, cement production and land-use change. This uptake has clearly reduced the human footprint on climate development. However, we cannot expect that the strength of these sinks will remain unaltered in the future as the processes that are involved are sensitive to climate change. This is in particular the case for the Arctic where ocean circulation changes, sea-ice and permafrost thaw and increased land and ocean primary production all excerting direct influence on CO2 and methane are expected to occur. Further, the ocean uptake of CO2 leads to ocean acidification that may have deletorious effects on many marine organisms. The Arctic Ocean appears particularly vulnerable to this threat. In this contribution we provide an overview of the land and ocean components of the Arctic carbon cycle and their climate change sensitivities.