Scientists have long speculated that our planet’s climate system is intimately linked to the Earth’s celestial motions.
The pacing of the most recent ice ages, for example, is attributable to changes in the shape of our planet’s orbit around the sun as well as to cyclic changes in the tilt of the Earth on its axis and its “top-like” wobble on that axis, all of which combine to influence the distribution and intensity of solar radiation.
Now, it turns out that variations in the axial tilt — what scientists call “obliquity” — of the planet have significant implications for the rise and fall of the Antarctic Ice Sheet, the miles-deep blanket of ice that locks up huge volumes of water that, if melted, would dramatically elevate sea level and alter the world’s coastlines.
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.