Sensitivity of the West Antarctic Ice Sheet to 2 Degrees Celsius (SWAIS 2C): Did a trans-Antarctic seaway open in a warmer-than-present world?

点击翻译按钮获取中文摘要

The West Antarctic Ice Sheet presently holds enough ice to raise global sea level by up to 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 temperature exceeds 2 degrees celsius is currently unknown. At the current rate of CO2 emissions to the atmosphere, average global temperatures will be 1.5 degrees celsius and 2.0 degrees celsius above preindustrial levels in 10 and 20 years, respectively. 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 an international collaboration of scientists from nine countries in order to better forecast the size and timing of future changes. The international SWAIS 2C Project scientists will collect and study geological (rocks, sediments), 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 grounded ice sheet) during recent periods in Earth’s history when the average global temperature reached or exceeded 2 degrees celsius, a level anticipated within the next two decades. These types of geological studies will help us understand how much and how fast the ice melted during past warm periods and what processes are involved. 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 proposal will support German members of the SWAIS 2C project to study the chemical and physical properties of sediments deposited at different times in the past in order to determine what the climate was like and what environmental conditions prevailed at the drilling site during the past and if a trans-Antarctic seaway opened.