Global Warming, Version 1.0 - St. Louis News - Daily RFT

The temperature dropped nine degrees Fahrenheit, which doesn't seem like much. (Really, that kind of drop is pretty normal for an early spring day in St. Louis.) But it was enough to create massive glaciers that wiped out about 75 percent of all the tiny proto-animals.
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​Fike and his team analyzed samples of limestone fossils taken from Quebec, Canada, and the environs of our very own part of Missouri using a "paleothermometer," a technique developed by a professor at the California Institute of Technology. The paleothermometer measures how much heavy isotopes of carbon and oxygen clump together in the limestone. The colder the temperature, the more the isotopes clump -- leaving a record in the rocks.
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Amazingly, some of the little sea animals managed to survive. But what really finished them off was a spell of global warming.

"Organisms...had adapted to the cold and suddenly the sea level rises and you're going out of the glacial period and temperatures get a lot hotter, and clearly some organisms are not happy with that," says Fike.

But, hey, now we know just how much heat and cold a brachiopod could stand.