Vulnerability and resilience of continuous permafrost systems to climate change

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Despite a well-documented warming trend in Arctic climate and a corresponding increase in permafrost temperatures there remains tremendous uncertainty about the response of continuous permafrost systems to climate change. Several model-based studies suggest widespread terrain instability, melting and disappearance of permafrost, while recent field-based studies indicate that permafrost systems may be more resilient than modelling scenarios imply. Generalizations concerning permafrost response to climate change can result in errors in estimates of carbon flux and landscape change. There is an urgent need for empirical observation of heat and moisture fluxes for the active layer and the upper part of permafrost to better constrain modeling activities. The primary goal of this research is to assessment of the vulnerability of key continuous and high Arctic permafrost systems to climate change by focusing on thermodynamic processes in the active layer and at the active layer permafrost interface. Field sites on Ellesmere, Axel Heiberg and Herschel Islands will include areas characterized by ice wedge systems, wetlands, and tundra landscapes underlain by ground ice (including massive ice and ice cemented ground). By making detailed measurements of boundary layer climate, surface temperature, temperatures, and mass and energy fluxes through the active layer and at the permafrost table coupled with observations on seasonal snow depth and distribution, vegetation, and local topographic changes for specific geo-ecosystems this research will contribute a better understanding about the dynamic relationship between climate inputs and permafrost response. By looking at permafrost as a complex system this study will identify various feedback processes that contribute to system resiliency and potential tipping points. It is well understood that once widespread thermokarst begins permafrost systems become highly unstable and the normal self regulating processes often require decades to re-establish a new equilibrium. By coupling measurements of CO2 and CH4 flux to these observations this study not only defines the thresholds of change but potential feed backs to the climate system.