Tackling an Ice Age mystery
Thursday, September 5, 2013 - 06:00
in Paleontology & Archaeology
In the northern hemisphere, ice sheets ebb and flow in 100,000-year cycles, driven by varying amounts of sunlight falling on Earth's surface as its orbit and orientation toward the sun changes. But astronomical variations alone cannot explain why ice ages develop gradually but end quickly, in a few thousand years. Though the last ice age saw several peak-periods of sunlight, it was the last one—about 10,000 years ago—that caused the ice to withdraw from much of Europe and North America.