Short Answer – yes. And almost everything died.
Would you ever go on vacation to the North Pole? Unless you like subzero temperatures and Nordic-ski treks, probably not. But if you lived 56 million years ago, you might answer differently. Back then, you would have enjoyed balmy temperatures and a lush green landscape (although you would have had to watch out for crocodiles). That’s because the world was in the middle of an extreme period of global warming called the Paleo-Eocene Thermal Maximum, when the Earth was so hot that even the poles reached nearly tropical temperatures.
But was the planet ever as hot as it is today, when every month the globe seems to be breaking one high-temperature record after another?
It turns out that the Earth has gone through periods of extreme warming more than once. The poles have frozen and thawed and frozen again. Now, the Earth is heating up again. Even so, today’s climate change is a different beast, and it’s clearly not just part of some larger natural cycle, Stuart Sutherland, a paleontologist at the University of British Columbia, told Live Science.