California Governor Jerry Brown will open the Global Climate Action Summit in San Francisco on Wednesday in an effort to show leadership on the issue of climate change — and to dissent from the position of President Donald Trump, who pulled the U.S. out of the Paris Climate Accords last year.

The conference bills itself as “a launchpad for deeper worldwide commitments and accelerated action from countries—supported by all sectors of society—that can put the globe on track to prevent dangerous climate change and realize the historic Paris Agreement.”

Announcing the summit last year, Gov. Brown told activists: “I know President Trump is trying to get out of the Paris Agreement, but he doesn’t speak for the rest of America. We in California and in states all across America believe it’s time to act, it’s time to join together and that’s why at this Climate Action Summit we’re going to get it done.”

Brown has made climate change the centerpiece of his economic agenda, supporting the renewal of California’s cap-and-trade program last year and championing the California High-Speed Rail System. He has also jet-setted across the world — burning many tons of carbon in the process — to participate in international conferences on climate change. Last year, he told a meeting at the Vatican that the world needed a “brain washing” on climate change.

In 2015, Brown signed a multi-national agreement among several regions, states, or provinces in which each committed to reducing emissions. The Global Climate Action Summit is an extension of that effort, focusing on what sub-national groups and governments can do.

Despite pulling out of the Paris agreement, the U.S. led the world last year in reducing carbon emissions by 0.5%. Without a carbon tax, a national cap-and-trade system, or the tight restrictions on fossil fuels favored by the Obama administration — which are being overturned by the Trump administration — the U.S. has reduced emissions over the past decade even while growing its economy, largely by switching to cleaner fuels like natural gas (over the objections of many environmentalists).

Last Saturday, ahead of the anticipated opening of the conference on Wednesday, climate change activists held marches in several American cities. Thousands marched in San Francisco itself.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He is a winner of the 2018 Robert Novak Journalism Alumni Fellowship. He is also the co-author of How Trump Won: The Inside Story of a Revolution, which is available from Regnery. Follow him on Twitter at @joelpollak.