Scientists have long speculated that our planet’s climate system is intimately linked to the Earth’s celestial motions.
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.
Read more at University of Wisconsin-Madison
Image: Roughly 15 million years ago, when Earth's atmosphere was supercharged with carbon dioxide, oceans warmed and sea ice around Antarctica disappeared, causing a significant part of the Antarctic ice cap to melt and dramatically elevate global sea levels (left). New research warns that a warming world caused by increased carbon dioxide in the atmosphere and coupled with periodic changes in the geometry of Earth's orbit could warm oceans, leading to a loss of sea ice (right) and sparking a dramatic retreat of the Antarctic Ice Sheet, and elevate sea levels worldwide. (Credit: Richard Levy)
