Permafrost stability in and around three North Slope Borough communities in Alaska

The impact of climate warming on permafrost and the potential of climate feedback resulting from permafrost thawing have recently received remarkable attention. Climate warming promotes an increase in permafrost temperature and active layer thickness, which, in turn, affect the stability of northern ecosystems, threaten infrastructure, and cause the release of carbon dioxide and methane into the atmosphere. The timing and the rate of permafrost degradation are two of the major factors in determining the anticipated negative impacts of climate warming on the Arctic ecosystems and infrastructure. The results of permafrost and active layer temperature observations (from the ground surface down to 1.5 m) at the three North Slope Borough communities of Point Lay, Wainwright, and Utqiagvik will be presented in this paper. Ground temperatures were measured both in natural conditions around the villages and under residential and commercial buildings to estimate the impact of infrastructure on permafrost stability. Generally, for all three villages, permafrost is still thermally stable. The mean annual ground temperature at 1.5-m depth is typically below -4°C for both natural conditions and under the elevated above ground engineering structures. One of the exceptions is thermokarst depressions such as deep troughs or ponds filled with water within and outside of the village of Point Lay. The mean annual water temperature at the bottom of some of these ponds with the water depth more than 0.5 m approaches the 0°C threshold, and in some cases even exceeds it, which can trigger development of a talik under these depressions. This may accelerate permafrost degradation at these locations with certain negative consequences for the stability of the village infrastructure and may manifest in numerous hazards for the residents. The methods of stabilization of permafrost and mitigation of adverse impacts of permafrost degradation will be discussed in this presentation. To enhance our understanding of possible future rates and pathways of permafrost degradation and to predict the consequences to residents, accurate high spatial resolution permafrost models are needed. Establishment of these models is possible only by integrating available high-resolution environmental data and by the assimilation of existing field and remote sensing data and observations into these models. The use of high-resolution (30x30 m) stand-alone permafrost dynamics GIPL2 model will be discussed to illustrate how changes in climate and further development of infrastructure will affect permafrost and people in this area.