Writing this week (Jan. 14, 2019) in the journal Nature Geoscience, a team led by Richard Levy of New Zealand’s GNS Science and Victoria University of Wellington, and Stephen Meyers of the University of Wisconsin-Madison describes research that matches the geologic record of Antarctica’s ice with the periodic astronomical motions of the Earth. Comparing the two records, the New Zealand and Wisconsin researchers recapitulate the history of the Antarctic Ice Sheet throughout most of the past 34 million years, starting when the ice sheet first formed.
Underpinning the new perspective of the Antarctic Ice Sheet is a refined assessment of the sensitivity of the Earth’s climate system to changes in obliquity, a powerful tool for probing the icy history of Antarctica.
The research is important because it teases out the pattern of growth and decay of the ice sheet over geologic time, including the presence of sea ice, a thin and fragile layer of frozen ocean surrounding Antarctica. A critical finding suggests that in a world warmed by a growing amount of atmospheric carbon dioxide, a loss of sea ice would likely amplify the cyclic effects of the Earth’s obliquity on the ice sheet as ocean waters warm. A loss of sea ice due to warming climate could trigger instability of the Antarctic Ice Sheet with dire implications for global sea levels.