Former US Vice-President Al Gore, speaks at the Securing a Sustainable Future for the Amazon, during the World Economic Forum in Davos, Switzerland, on January 22, 2020.

Former U.S. Vice President Al Gore believes the climate crisis is getting worse "way faster" than most people realize, describing it as a "challenge to our moral imagination."

Delivering closing remarks at a World Economic Forum panel session on Wednesday, Gore spoke passionately about the climate emergency.

At one stage, the co-founder of Generation Investment Management compared the scale of the crisis to a number of infamous historic events.

It is "way worse" than many realize and intensifying "way faster" than people appreciate, Gore said.

"This is Thermopylae. This is Agincourt. This is Dunkirk. This is the Battle of the Bulge. This is 9/11," he added.

Gore's comments follow the the hottest year on record for the world's oceans, the second-hottest year for global average temperatures, and wildfires from the U.S. to the Amazon to Australia.