“In both cases, there is no plan to deal with crisis,” he added.
Moreover, Mr. Trump has steadily dismantled the climate change plan that was already in place by effectively gutting the federal government’s authority to do anything to lower greenhouse gas pollution.
“We had at the end of the Obama administration the first-ever federalwide regulatory regime on climate,” said David G. Victor, the director of the Laboratory on International Law and Regulation at the University of California, San Diego. “Most of that, the Trump administration has actively rolled back.”
In his first months in office, Mr. Trump announced that he would withdraw the United States from the 2015 Paris climate accord, under which nearly every country in the world had pledged to reduce emissions of planet-warming pollution.
Domestically, Mr. Trump directed Andrew Wheeler, the current head of the Environmental Protection Agency, to dismantle a suite of major climate change regulations put in place by the Obama administration, which had been designed to target pollution from the nation’s three largest sources of greenhouse emissions: coal-fired power plants, auto tailpipes and oil and gas drilling sites. Taken together, those rules represented the country’s first significant step toward reducing greenhouse gases, while putting the world’s largest economy at the forefront of the global effort to fight climate change.
Now they are in shambles.
In August, the E.P.A. completed the legal process of rolling back rules on methane, a powerful climate-warming gas emitted from leaks and flares in oil and gas wells. In April, it completed its rollback of the rules on tailpipe greenhouse pollution. And in June 2019, it replaced the Obama-era rule requiring coal plants to reduce emissions with a new rule devised to allow the plants to continue to release far more pollution.
If Mr. Biden is elected, he has vowed to rejoin the Paris agreement and reinstate those rules, while pushing to enact even stronger policies, spending up to $2 trillion to promote the development of renewable energy sources such as wind and solar.
But experts said it may take far more than that to rebuild the American climate change legacy — or its ability to persuade other governments to take similar action. That is a profound consequence, the experts said, because climate change is a global problem and cannot be meaningfully mitigated unless the world’s largest polluters all work in concert.