President Biden called combating climate change “a moral imperative” as he convened a two-day virtual summit of dozens of world leaders with the aim of putting the United States back at the forefront of the global issue after a retrenchment under President Donald Trump.

“This is a moral imperative, an economic imperative, a moment of peril but also a moment of extraordinary possibilities,” Biden said from the White House. “Time is short, but I believe we can do this.”

Participants in the summit are expected to include Chinese President Xi Jinping, Russian President Vladimir Putin, British Prime Minister Boris Johnson and German Chancellor Angela Merkel, among many others.