Near-Snowball Earth states and their implications for the deep-time climate of Earth and the habitability of extrasolar planets

Supervisor: Aiko Voigt (Department of Meteorology and Geophysics) in collaboration with Dorian Abbot (University of Chicago)

Funding Situation: supervisor has secured funding

Project outline: This study aims to clarify the role of land, ocean and sea-ice processes for near-Snowball Earth states in which almost all of Earth’s surface is covered by ice apart from a narrow strip of open tropical ocean. The pan-glaciations of the Neoproterozoic (1000-541 Million years before present) are the most extreme ice ages in Earth’s history, with widespread tropical glaciers that reached down to sea level. In contrast to the classical Snowball Earth of a completely ice-covered planet, near-Snowball Earth or waterbelt states might be able to explain the geological evidence as well as the survival of life. However, waterbelt states so far have only been demonstrated in idealized climate models without continents and ocean dynamics. The study aims to close this gap by means of the global ICON climate model in a hierarchical setup that addresses the impact of continents, subtropical wind-driven ocean cells, and ocean and sea-ice dynamics more generally. The ultimate goal of the project is to test if a waterbelt state can exist in a coupled version of the ICON model that includes atmosphere and ocean dynamics as well as realistic continents, and if such a state can exist over a large enough range of atmospheric CO2 to explain Neoproterozoic geology. The study will involve a collaboration with Dorian Abbot from University of Chicago and offers ample opportunities to interact with colleagues from geology and astrophysics to elucidate implications for Earth’s climate history and the possibility for life on other planets.