U.S. President-elect Joe Biden on Saturday introduced key members of the team he is assembling to fulfill his pledge to combat climate change, calling them brilliant and qualified.

Climate change is "the existential threat of our time,” Biden said, and the people he was nominating to lead the Environmental Protection Agency, the White House Council on Environmental Quality and the departments of Energy and Interior will be "ready on day one.”

"We need a unified national response to climate change. We need to meet the moment with the urgency it demands, as we would with any national emergency, ” Biden said at an event in Wilmington, Delaware.