How an ancient climate change catastrophe holds vital clues about the Earth's future

...The PETM is the Paleocene Eocene Thermal Maximum — an ungainly name for the time that’s considered one of Earth’s best analogues to this era of modern, human-caused global warming. In a matter of a few thousand years, huge amounts of carbon were injected into the atmosphere, causing global temperatures to rise between five and eight degrees Celsius. The rapid climate change disrupted weather, transformed landscapes, acidified oceans and triggered extinctions. It took more than 150,000 years for the world to recover. If history is allowed to repeat itself, the consequences for modern life could be similarly long-lasting — which is why Wing is so determined to understand this ancient climate catastrophe. Chalk deposits at the bottom of the ocean began to dissolve as carbon dioxide made seawater more acidic. Fossils of tiny, deep sea-dwelling creatures showed evidence of an oxygen shortage — a sign that the water was getting warmer. Everywhere in the ocean, creatures adapted to the changed environment, or else they died out. On land, mammals got smaller and smaller. Ancient ancestors of horses, tiny to begin with, shrunk 30 percent to the size of house cats. Abigail Carroll, a paleoclimatologist at the University of New Hampshire, said this was probably an adaptation to the warmer weather: Smaller bodies are easier to keep cool...MORE

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