Speakers included 350.org founder Bill McKibben, The Green Collar Economy author Van Jones, activist and “Big Little Lies” star Shailene Woodley, climate scientist Brenda Ekwurzel, activist and musician Xiuhtezcatl Martinez and Mayor Dale Ross of deep-red Georgetown, Texas, whose pragmatic embrace of newly cheap renewable energy has made him a poster boy for how Republicans could quit climate change denialism.

Rep.-elect Alexandria Ocasio-Cortez (D-N.Y.), who has made championing a so-called Green New Deal her first priority since arriving in Washington, emerged as the fiercest voice on the panel Monday.

“This is going to be the Great Society, the moon shot, the civil rights movement of our generation,” she said. “That is the scale of the ambition that this movement is going to require.”

In the 2016 presidential election, Sanders staked out the most ambitious climate platform of any candidate, vowing to slash carbon dioxide pollution 40 percent by 2030, end fossil fuel subsidies and ban fracking. Despite stark policy differences with his chief rival in the primaries ― former Secretary of State Hillary Clinton supported fracking and raised twice as much from the oil and gas industry as her Republican opponent ― climate change remained a policy backwater in the election.