CONSTRAINING RAPID CLIMATE CHANGE IN THE LAURENTIAN GREAT LAKES REGION, FIRST STEPS: TUNING A LAKE WATER PROXY SYSTEM MODEL FOR QUANTITATIVE PALEOCLIMATE INTERPRETATIONS

The Laurentian Great Lakes region is home to 10% of the US population and produces >20% of US GDP. With abundant freshwater and a mild climate, this region has been billed as a haven for climate refugees. Yet, this century, the Great Lakes region is predicted to experience increasingly variable precipitation patterns, with wetter winters and drier summers, due to rapid (defined as several °C warming per century) anthropogenic climate change. Such predictions have large uncertainties that are critical to reduce, as climate will dictate mitigation responses and the population size that this region can support. Historical observations cannot constrain the response to rapid warming, as they span a relatively short period of history with minimal climatic change. Paleoclimate records can quantify precipitation change during times of past rapid warming, thus providing critical constraints for the response to ongoing and future warming.

This project aims to use lacustrine climate proxies to constrain past changes in temperature, moisture balance, and precipitation isotopes in the Laurentian Great Lakes region during rapid warming events at 14.5, 11.7, and 8.0 ka. Climate proxies from lacustrine archives are complex and influenced by multiple variables related to regional climate and local (lake- and catchment-scale) processes. Lake water proxy system models (PSMs) provide a means to test the sensitivity of proxies to both regional and local changes, enabling quantitative interpretations of paleoclimate records. We present initial results from Red Pond, a small, closed-basin lake that lies on the Last Glacial Maximum terminal moraine of the Laurentide Ice Sheet in southwestern New York State. We use limnological data collected monthly (temperature, dissolved oxygen, turbidity, and lake water stable hydrogen and oxygen isotope values) to set up and tune a PSM for Red Pond. Using the results of the tuned PSM and initial sensitivity tests, we will explore this lake’s potential as an archive of past rapid climate change in the region. Our future research will generate and interpret paleoclimate proxy records from lake sediment cores collected from Red Pond, with the goal of placing constraints on the climate response of this region to rapid warming events.