The Arctic Carbon Cycle and its Response to Changing Climate

Abstract:

The Arctic has experienced the most rapid change in climate of anywhere on Earth. Over the last half century, the mean annual surface temperature has increased at over twice the rate of the global average.
This polar amplification of surface air temperature is likely to have far ranging effects on the carbon cycle. After briefly reviewing the range of physical responses to climate change in the Arctic and what we can expect in the future, I will discuss the current evidence for changes in the Arctic carbon cycle both from the top-down (atmospheric observation) point of view, and from the bottom-up (flux measurement) point of view. In particular, we will look at the results of ensembles of atmospheric inversions for both CH₄ and CO₂, and we will compare these views of the atmospheric to terrestrial ecosystem models and flux products to answer the question of whether the top-down and bottom-up observations agree. We also consider whether or not it is possible to learn about changes in Arctic emissions from gradients in atmospheric observations without detailed consideration of atmospheric transport.