Columbia University

Tackling an Ice Age mystery

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 ...

dateSep 05, 2013 in Earth Sciences
shares0 comments 0

What geology has to say about global warming

Last month I gave a public lecture entitled, "When Maine was California," to an audience in a small town in Maine. It drew parallels between California, today, and Maine, 400 million years ago, when similar geologic processes ...

dateJul 14, 2014 in Earth Sciences
shares0 comments 195