President Trump has vowed to remove the United States from the historic Paris climate agreement, which every nation on Earth has now signed onto. Democratic presidential nominee Joe Biden has said one of his first acts as president, should he win, will be to keep America in that accord.

In this special episode of Climate 2020, the director of WWF's U.S. climate program and We Are Still In movement co-founder Elan Strait talks about the growing power of the sub-national movement in America - and what it means beyond this election cycle.