Collaborative Research: Sensitivity of the West Antarctic Ice Sheet to 2° Celsius (SWAIS 2C)

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This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). The West Antarctic Ice Sheet presently holds enough ice that it would raise global sea level by five meters if it all melted. Information from satellites demonstrates that the West Antarctic Ice Sheet is losing ice faster than any other region in the Antarctic. However, how much of the West Antarctic Ice Sheet will melt and how quickly it will happen when average global temperatures exceed 2 degrees C is currently unknown. At the current rate of CO2 emissions to the atmosphere, average global temperatures will be 1.5 degrees C and 2.0 degrees C above preindustrial levels in 10 and 20 years, respectively. Virtually all pathways to restrict the increase in global temperatures to 1.5 degrees C now require direct carbon removal from the atmosphere. Sea level rise is one of the clearest planet-wide signals of this human-induced climate change. Global mean sea level has increased by ~22 cm since 1880 and will continue to rise well beyond the 21st century. Given the far-reaching and international consequences of Antarctica's future contribution to global sea level rise, the SWAIS 2C Project was developed through international collaboration to better forecast the size and timing of future changes. The Sensitivity of the West Antarctic Ice Sheet to 2⁰ Celsius (SWAIS 2C) Project scientists will collect and study geological (rocks), glaciological (ice), and geophysical (Earth physical properties) data and provide new information to guide the development of climate and ice sheet numerical models to better understand and predict how the ice sheet on West Antarctica will contribute to future sea level rise. The project aims to interpret the state of past environmental conditions in West Antarctica (warm open marine seas, cold ice-covered ocean, or polar grounded ice sheet) during recent periods in Earths history when average global temperatures reached or exceeded 2 degrees C, levels anticipated within the next two decades. These types of geological studies will help us understand how much ice melted during past warm periods, what processes are involved, and how fast it will change. Glaciological and geophysical information collected by scientists will help us better understand the modern processes that cause the ice sheet to grow or melt. Modeling studies will use this new information regarding past and present ice sheet behavior to make better predictions of how much and how fast the West Antarctic Ice Sheet will melt in the future. This project will support a United States scientific team with a range of scientific expertise, with a key goal of broadening the involvement of early career scientists in Antarctic research. Informative and impactful education and outreach materials will be developed and shared with educators to bring polar science into the classroom and provide accurate information related to ice sheets stability, sea level rise, and global climate change to students and the public.Satellite observations show that the West Antarctic Ice Sheet (WAIS) is losing mass at an accelerated rate, much faster than other Antarctic regions. WAIS is considered highly sensitive to future warming because much of it is grounded 2500 m below sea level and its associated floating ice shelves are exposed to warming ocean waters. Future collapse of marine-based sectors and full melting of the WAIS has the potential to raise global mean sea level by 5 meters. However, Antarctic ice sheet dynamics remain the largest uncertainty in numerical model projections of future sea level rise. Existing datasets lack direct physical evidence of WAISs response to past times when global mean temperatures were 2 degrees C warmer than during pre-industrial time. The Sensitivity of the West Antarctic Ice Sheet to 2⁰ Celsius (SWAIS 2C) project is a four-year project developed through international collaboration to integrate geological, glaciological, and geophysical data with ice sheet and climate modeling studies to better project future scenarios of WAIS contribution to sea level rise. This approach will aim to integrate studies of past (using geological records) and present (using glaciology and geophysical records) ice sheet behavior to inform future projections (using models) of WAIS response to climate change. This project will recover two ~200 m-long sediment cores from beneath the WAIS using new drilling technology in strategic locations adjacent to the grounding zone at Kamb Ice Stream and at Crary Ice Rise in the inner Ross Embayment along the Siple Coast. Three SWAIS 2C approaches will determine conditions associated with past WAIS collapses and will sharpen our predictive tools to assess its future stability in our warming world: (1) stratigraphic records will provide new paleoenvironmental information regarding past sensitivities to system boundaries, processes, and rates of change; (2) modern observations will provide details of the variables and complexities associated with processes and rates of change; and (3) numerical model application and development will assess future scenarios to equilibrium states in accelerated time, and test system sensitivities and feedbacks. SWAIS 2C Project results will contribute new information from the southern end (most proximal to the ice grounding zone) of a transect that extends north to recent drill holes in the outer Ross Embayment to connect with distal Southern Ocean records. The SWAIS 2C Project is complementary to the US-UK Thwaites Glacier Project on the other side of West Antarctica, allowing for a broader understanding of WAIS history and more accurate predictions of future change. A major goal of this project is to broaden development of early-career scientists in polar research and work closely with teaching professionals to provide new, impactful, and assessable classroom material to educators, and accurate information related to ice sheets stability, sea level rise, and global climate change to the public.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.