Geochemical approaches for cryosphere studies on glacial-interglacial timescales

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The earth system is on a trajectory towards a climate state that is similar to the warmest intervals of the last several million years, and the impacts of this warming are already apparent in the north. In large part, the impacts of climate change in northern environments are exacerbated by feedbacks involving the cryosphere - glaciers, ice sheets, permafrost, and sea ice. The proposed research program will use geochemical research tools to address the following overarching questions: how did elements of the arctic cryosphere (e.g. ice-sheets, glaciers, and permafrost) respond during periods of sustained climate warming over the last several 100,000 years and, in turn, how did these responses feed back into earth-system processes like sea-level rise, carbon cycling, and regional hydrological change? The proposed research program includes three quasi-independent strands that collectively tackle these overarching question. These strands will address the following themes: (1) Greenland ice-sheet retreat and associated landscape change during sustained intervals of climate warming; (2) developing methods to determine, on a landscape-scale, the extent of permafrost degradation during sustained past warm intervals; and, (3) indirect impacts of cryospheric change on northern landscapes and earth-system processes. This research program will provide new approaches and important insights into important scientific and societal questions. The interglacial periods I propose to study are perhaps the most accessible geological analogues for what landscapes and earth-system processes will be like in the warmer Arctic that is projected for the coming century. There will be wide scientific and public interest in the results of the proposed research on permafrost response through past warm intervals, given the potential carbon cycle feedbacks and infrastructural challenges inherent in widespread permafrost thaw. Research on Greenland ice-sheet retreat during past sustained warm intervals will also yield highly significant conclusions, given the substantial scientific interest in contemporary Greenland ice-sheet behaviour and the compelling public interest in assessing its potential contribution to future sea-level rise.