Credit: Cem Ozdel/Anadolu Agency/Getty Images

Speaking at the United Nations on Monday, Robert Redford urged world leaders to take action now to combat climate change.

“We are all responsible for this crisis,” Redford said in a passionate speech during a high-level meeting of the U.N. General Assembly on climate change. “Your mission is as simple as it is daunting: save the world before it’s too late.”

“Nothing less than the fate of our planet will hang in the balance,” the actor and environmental activist added.

Redford also asked world leaders to “assume a leading role” in tackling climate change at an upcoming conference on the matter in Paris in December.

“This December, the world must unite behind a common goal,” he said. “Because look, this is it. This is our only planet, our only life source. This may be our last chance.”

You can watch Redford’s full speech in the video below.