CAREER: South Greenland's Holocene Climate History Reconstructed Using Three Paleolimnological Approaches

Project Summary ***DRAFT*** CAREER: South Greenland’s Holocene Climate History Reconstructed Using Three Paleolimnological Approaches Overview: Paleoclimate data provide our only empirical observations of how the arctic system responds to major sustained climate change. It is especially urgent to understand how past climate change unfolded in Greenland, where mass loss from the Greenland Ice Sheet will drive a large fraction of future sea level rise. Meteorological and paleoclimate data from south Greenland suggest that climate trends there may diverge from hemispheric trends, with potential consequences for ice sheet mass balance and other impacts of anthropogenic climate change. The proposed research will assess this hypothesized divergence through the Holocene, and address major questions about the dynamics and consequences of climate change on Greenland, by developing a suite of new Holocene climate reconstructions from south Greenland using three independent approaches in lake sediments: quantitative temperature reconstructions based on insect assemblages; reconstructions of precipitation isotopes (reflecting changes in atmospheric circulation patterns) using a relatively new method based on chironomid 􀁇18O; and reconstructions of alpine glacier fluctuations based on sediments from lakes with extant glaciers in their watersheds. This CAREER proposal’s research and educational goals share the common thread of promoting better understanding of climate change. As an extension of the PI’s background in public outreach, science communication and cross-disciplinary education, one educational objective is to develop a new multi-disciplinary graduate seminar that will help train graduate students from sustainability-relevant STEM fields to communicate science beyond academia. The other major educational objective is to support teaching of climate science and sustainability in Chicago-area schools by developing two year-long professional development series that provide sustained support for K-12 teachers integrating cutting-edge climate and energy science into curricula. Intellectual Merit: This work would approximately double the number of continuous, quantitative Holocene terrestrial temperature reconstructions available from Greenland beyond the ice sheet, while also assessing any changes in atmospheric circulation and glacier mass balance that were associated with Holocene temperature changes over south Greenland. Continuous, quantitative paleotemperatures records will help characterize the magnitude and spatial patterns of arctic climatic responses to Holocene forcings, and improve the potential for data-model comparisons to test the performance of climate and earth system (e.g., ice sheet) models. Independent reconstructions of Holocene precipitation isotopes will be used to test hypotheses about changes in atmospheric circulation (e.g., in the dominant mode of the North Atlantic Oscillation) that accompanied past climate change – and, by extension, might accompany future climate change. By documenting local alpine glacier mass balance, and comparing results with glacial-geologic reconstructions of ice sheet fluctuations, this work will help clarify the role of local air temperatures and other atmospheric conditions in driving changes in the ice sheet through the Holocene – thus helping to evaluate the sensitivity of the Greenland Ice Sheet to future climate change. This work will also advance two methods: It will validate and apply an emerging isotopic proxy with potential for widespread applic