By Lydia O’Connor for Huffington Post. 

As kids of the ’90s can attest, Bill Nye the Science Guy is a pro at explaining complicated scientific phenomena, and he does just that in a new clip on climate change with National Geographic.

There are five things we need to know to understand climate change, the science educator says — the most important being that it’s happening at an unprecedented speed.

“All this never happened this fast,” he emphasizes. “That’s what you gotta get your heads around.”