Investigating Climate Variability changes of the last 130 000 years using an ice core from Skytrain Ice Rise, West-Antarctica (CliVarSky130)

• Applicant: Dr. Helene Hoffmann
• Subject Area: Atmospheric Science ; Oceanography
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 522419358

West-Antarctica is one of the globally most sensitive regions to the effects of climate change. A collapse of the West-Antarctic Ice Sheet in a warming climate would have dramatic consequences on the global sea level rise. Not only the rise of the global mean temperature will affect West-Antarctica, but to at least the same extent changes in the climate variability. These variability changes can nudge the sensitive system to tipping points, which in consequence can lead to irreversible changes in for example ice sheet dynamics. To better estimate the effects of these potentially abrupt changes is the future, the respective model projections must have a firm data basis. Paleoclimatic records, in this case retrieved from ice cores, can provide such a basis. Of special interest are thereby long-term records reaching back into the last glacial period or even the previous last natural warm period (about 110 000 – 130 000 years before present). Such long climate records from West-Antarctica are however sparse. Within the framework of the WACSWAIN project (WArm Climate Stability of the West-Antarctic Ice sheet in the last iNterglacial) a new ice core was recently drilled at Skytrain Ice Rise, which dates back to about 126 000 years before present. During WACSWAIN, comprehensive continuous datasets of the stable water isotope, the chemical impurity content and of the physical parameters were compiled and are now available for further analyses. Furthermore, for the first time selected sections of the core were analysed for their impurity content using the ultra-high resolution technique of laser ablation (LA-ICP-MS). This technique enables investigation of changes in unprecedented detail. The aim of this proposed project is therefore to use this high-resolution data in combination with the continuous records to statistically investigate climate variability in this specific region of West-Antarctica in unparalleled detail throughout the last glacial cycle. A special focus will be the investigation of phases of abrupt changes in proxies related to temperature and ice cover. For example, an observed sharp step change in the water isotope and marine ion content in the early Holocene. The statistical analyses of past climate variability (variance, amplitude, scaling effects) will then be used to better understand the currently observed changes in West-Antarctica. This will be further supported by testing of the hypothetical reasons for these changes via application of specific isotope enabled global circulation models and chemical transport models. This project will therefore yield an important contribution to the understanding of the West-Antarctic climate system in the past and the future.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 1158: Infrastructure area - Antarctic Research with Comparative Investigations in Arctic Sea Ice Areas
• International Connection: United Kingdom
• Co-Investigator: Professorin Dr. Kira Rehfeld
• Cooperation Partners: Dr. Elizabeth R. Thomas; Professor Dr. Eric W. Wolff