RECENT PERMAFORST DEGRADATION IN RESPONSE TO A CHANGING ARCTIC CLIMATE - LESSONS FROM THE NORTH SLOPE OF ALASKA (Invited Presentation)

The changing climate of the Arctic is causing changes to surface energy fluxes, which is in turn causing permafrost to degrade. On the North Slope of Alaska, we have tracked several permafrost degradation features for over 7 years, assessing both impacts to downstream waters and ground temperature regimes. These features include large thaw slumps and deeply incised ice-wedges that have thawed. In their active degradation periods, these features release significant amounts of sediment and nutrients, with direct impacts to receiving waters. Shallow (<3 m) ground temperatures are dynamic during this period, with variable annual means that are highly sensitive to surface conditions. However, after the first couple of years, as feautres stabilize and vegetation begins to re-grow within them, release of sediment and nutrients drops off substantially, and ground temperatures tend to be a bit more buffered from surface energy balance changes. While these features are remarkable when fresh (and even as they begin to 'recover'), their substantial impacts on the landscape and river networks tend to occur in 'pulses' of a few years, prior to a period of stabilization and re-vegetation that is likely to last beyond a decade.