Take a moment to imagine you are in a completely different place. You are surrounded by lush, broad-leafed vegetation. The temperature is a balmy average of 12°C and in the distance you see a lemur-like creature gliding from tree to tree, enjoying the sunshine.

Where do you think you are? Surprisingly, you are 100 km above the Arctic Circle during the extreme warming event of the Paleocene-Eocene Thermal Maximum (PETM) about 55 million years ago!