The Erosion of Permafrost Coasts: What We Know and What We do not Know
Permafrost coasts make 34 % of the coasts of the Earth and are likely to become one of the most impacted environments of the Earth under changing climate conditions. The lengthening of the open-water season and the increasing open-water area, due to the decline of sea ice extent, will induce changes to the length of the fetch and allow storms to hit the coasts further in the fall season. These storms are thought to bear staggering threats to the coasts in the form of destruction of community and industry infrastructure as well as dramatic changes in sediment and nutrient pathways in the nearshore zone. Examples from northern Alaska show that low-lying coasts are particularly sensitive to these changing conditions and already see increasing erosion rates. A recent thorough systematic investigation of the coast at the circum-Arctic scale has brought new numbers on erosion and release of organic carbon from eroding shorelines. This presentation shows this end product (a coastal classification segmenting the arctic coast in more than 1300 stretches of coast) and the numbers stemming from it. The presentation will highlight the similarities and differences between the different seas in the Arctic and the contribution of coastal erosion to nearshore sediment budget. It will also largely refer to the recent State of the Arctic Coast 2010 report which showed the relevance of this erosional process to the biological and socio-economical frameworks in the coastal zone of the Arctic.