Jerry Brown: 'We are talking about extinction.'

Governor Jerry Brown, issuing an ominous appeal on climate change, spoke at a climate change conference in Vatican City on July 21, 2015, saying the world may already have "gone over the edge" on global warming and that humanity must reverse course or face extinction. Brown, speaking at a summit of mayors from around the world, increased his already-high profile on climate change, working to coalesce support for carbon reduction policies ahead of global climate talks in Paris in December. Pope Francis, who organized the conference after the release of his encyclical on climate change, told the group through an interpreter that he has "great hope ... that a fundamental basic agreement is reached" among global leaders.

Brown’s remarks reflected the urgency of the effort but also its limitations.

"We don’t even know how far we’ve gone, or if we’ve gone over the edge," Brown said. "There are tipping points, feedback loops. This is not some linear set of problems that we can predict. We have to take measures against an uncertain future which may well be something no one ever wants. We are talking about extinction. We are talking about climate regimes that have not been seen for tens of millions of years. We’re not there yet, but we’re on our way."

Many Republicans have said the effects of climate change are overstated. As he has several times, Brown called them "troglodytes," to applause. But the Democratic governor went beyond partisan rabble-rousing, quoting balefully from St. Paul’s biblical message to the Galatians.

"God is not mocked," Brown said, "for whatsoever a man soweth, that shall he also reap."

In a room full of like-minded mayors, Brown was repeatedly held out as a global leader on climate change. With a large proportion of the world’s population living in cities, mayors are considered significant to efforts to reduce greenhouse gas emissions.

New York City Mayor Bill de Blasio, announcing his city would reduce its emissions by 40 percent by 2030, said New York was following "the example of our colleague here today, Gov. Jerry Brown," whom he called "the leading voice in our nation" on the issue.

San Francisco Mayor Ed Lee plans to phase out petroleum-based diesel from the city’s fleet. The fleet will use renewable diesel. 

Brown and dozens of mayors signed a declaration stating that "human-induced climate change is a scientific reality, and its effective control is a moral imperative for humanity." Brown has been prodding more states and sub-national governments to join California and several others in a non-binding pact to limit the increase in global temperature to below 2 degrees Celsius, a threshold beyond which many scientists predict major environmental disruption.

"We have to respond, and if we don’t the world will suffer, we will all suffer," Brown said. "In fact, many people, millions are suffering already."

Brown’s ambassadorship on climate change has afforded him the kind of international attention — if not the degree — that eluded him in three unsuccessful campaigns for president. Brown called climate change "an area where I can be constructive," and he suggested he might not hold such a platform on the issue if he had achieved higher office.

"Were I president, I probably would think about nuclear bombs, and I would be very concerned about what Mr. Putin is thinking, and what the Indians and the Pakistanis are doing with their nuclear bombs, and I’d want to make sure that we try to slow this all down," Brown said in an interview. "When you’re governor, you don’t have to talk about this international stuff. But climate change, because it is both local and global, it is a big existential threat that I can deal with as a governor."

Some scientists argue the world is unlikely to reduce carbon emissions enough to constrain rising temperatures, urging greater investment in adaptation measures to address sea level rise and other effects of global warming.

Brown, standing in sweltering heat on the roof of a television studio across town from the Vatican shortly after his address, said, "We’ll do all the adaptation. But if every year things get worse, our goose will be cooked."