WASHINGTON — Climate change was supposed to be one of Michael R. Bloomberg’s greatest strengths in the Democratic presidential primary.
Where other candidates have plans to reduce fossil fuel use, the billionaire philanthropist has results: millions of dollars spent to help close hundreds of coal-fired power plants and, in many cases, to secure a switch to natural gas, which produces about half the planet-warming greenhouse gases as coal.
But that transition, once considered a bragging right in the environmental world, has become a liability to his campaign at a moment when the only acceptable fossil fuel is no fossil fuel.
As he seeks to win over climate-conscious Democrats, Mr. Bloomberg has found himself unable to shake the incrementalist label in a maximalist primary. During his debut debate in Nevada, Mr. Bloomberg allowed that an economy powered solely by wind, solar and other renewable energy sources was “still many years from now.” Hydraulic fracturing for natural gas, or fracking, will continue “for a while,” he said, as he promoted natural gas as a bridge between coal and carbon-free power.
“You are not a climate fighter,” Josh Fox, the filmmaker who won acclaim for his 2010 film Gasland, said of Mr. Bloomberg on Twitter. “Your embrace of gas makes to you a #climateDenier and a hypocrite.”
In a CNN town hall forum on Wednesday, Mr. Bloomberg somewhat walked back his comments, calling natural gas “not all that much better, but somewhat better” than coal. Climate activists said they remained unimpressed.
“We need a Democratic candidate who understands the urgency of this crisis and who is cleareyed on the need to move away from all fossil fuels, and that includes gas,” said David Turnbull, spokesman for Oil Change U.S., a nonprofit environmental organization. “Bloomberg’s record on that remains murky.”
Greenpeace gave Mr. Bloomberg’s climate plan a C+.
“Bloomberg is a victim of the climate debate moving much faster than the positive realities he helped shape on the ground,” said Paul Bledsoe, a strategic adviser at the Progressive Policy Institute, a Democratic research organization. “In particular, his focus on coal seems passé now that the target of the left is natural gas.”
He called Mr. Bloomberg “one of the most important philanthropists on climate change in the last 15 years.”
Bloomberg campaign officials say his climate plan calls for halting the growth of natural gas and transitioning to 100 percent renewable energy “as fast as possible.” Mr. Bloomberg is funding legal challenges and local lobbying efforts against virtually every proposed new gas plant in the country. He had already helped to close 304 of the nation’s 530 coal-fired power plants.
That message does not seem to be breaking through. The environmental community has overwhelmingly embraced the Green New Deal, which demands an expensive and aggressively rapid transition from all fossil fuels before 2050.
Mr. Bloomberg has been working on climate change since former president George W. Bush pulled out of the world’s first global warming agreement, the 1997 Kyoto Protocol. In 2005, as mayor of New York City and a Republican, Mr. Bloomberg joined a bipartisan coalition of mayors who vowed to work toward the treaty’s emissions goals.
Just over a decade later, after President Trump announced that the United States would leave the Paris Agreement, Mr. Bloomberg poured millions of dollars into a similar effort to galvanize American cities, states and businesses to significantly reduce emissions, regardless of Washington’s intentions.
In the years in between, Mr. Bloomberg set and nearly met an ambitious goal of cutting New York City’s emissions 30 percent by 2030. He promoted a national carbon tax and, citing climate change, endorsed President Barack Obama’s re-election in 2012.
His most extensive and expensive campaign, though, has been to eliminate coal.
The Sierra Club had been working for about eight years to stop the construction of new coal plants when, in 2010, Mr. Bloomberg joined the effort and pushed for a new, data-driven course. The result, current and former Sierra Club leaders said, was not just a database of every coal plant and its details. It also included more than 1,000 individual boiler units, which produce the hot water or steam within the coal plant, their pollution profiles and how much it costs to keep them operating. With that information, activists could make the economic argument to close the plants.
“After nine months, we said, ‘We think we can shut down a third of the coal fleet in four years,” said Bruce Nilles, managing director at the Rocky Mountain Institute, who previously ran the Beyond Coal campaign and advises Mr. Bloomberg. The effort would cost $148 million, and Mr. Bloomberg provided the first $50 million. A few years later, he later more than doubled that.
“Even our most progressive politicians were still talking about ‘clean coal,’” Mr. Nilles said. “Mike Bloomberg came out and said, ‘I’m going to shut down coal.’ And he did it on a barge in front of a coal plant in Virginia.”
“It was a very clear message to Wall Street and everyone else that coal’s days were numbered,” Mr. Nilles said.
With Mr. Bloomberg’s money, activists, consultants and lawyers lobbied the Obama administration for new regulations on mercury, coal ash and other pollutants, and then calculated the cost of compliance for each individual plant. They then pressed local utility commissions to stop utilities from passing the costs of pricey new pollution controls on to ratepayers, and made the case that gas and solar power would be cheaper than retrofitting existing coal plants.
Since 2010, about 246 coal plants have closed while another 60 have announced plans to shut down — about 40 percent of coal generating capacity in the United States. That represents 456 million metric tons of carbon dioxide not pumped into the atmosphere, according to the Sierra Club.
Michelle Bloodworth, president of the American Coalition for Clean Coal Electricity, which represents coal producers, said the closings were driven by low gas prices and regulatory uncertainty, not Mr. Bloomberg. Last year The Associated Press said the markets, not Mr. Bloomberg’s money, are killing coal.
“That dichotomy is kind of dumb,” said Tom Sanzillo, finance director for the Institute for Energy Economics and Financial Analysis, who worked with the Beyond Coal Campaign. He credited the markets with enabling activists to take on coal, which for decades had rarely been successfully challenged.
Leah C. Stokes, a political scientist at the University of California, Santa Barbara, said public utility commission proceedings were “battles between utilities and whoever else shows up who is well resourced enough to make it there.” Those resources came from Mr. Bloomberg.
Many environmental activists are not having it.
“He does deserve credit for investing in the fight against coal, but he still hasn’t owned up to the fact that most of the coal plants that were closed were replaced with natural gas, produced with fracking,” said Mitch Jones, the climate and energy program director at Food and Water Watch.
Mr. Bloomberg’s senior adviser on climate change, Antha Williams, said the candidate believed that the role of gas as a bridge fuel has ended. She and others noted that last year he initiated a new $500 million campaign to not just eliminate the country’s remaining 150 coal plants but also stop the growth of natural gas.
“Now that renewable energy is cheaper than gas in most places and gas is now a bigger source of carbon pollution than coal, he has already started working to move America completely off fossil fuels,” Ms. Williams said.