Representatives of American cities, states and companies are preparing to submit a plan to the United Nations pledging to meet the United States' greenhouse gas emissions targets under the Paris climate accord, despite President Trump's decision to withdraw from the agreement.
The unnamed group — which, so far, includes 30 mayors, three governors, more than 80 university presidents and more than 100 businesses — is negotiating with the United Nations to have its submission accepted alongside contributions to the Paris climate deal by other nations.
"We're going to do everything America would have done if it had stayed committed," Michael Bloomberg, the former New York City mayor who is coordinating the effort, said in an interview.
By redoubling their climate efforts, he said, cities, states and corporations could achieve, or even surpass, the pledge of the administration of former President Barack Obama to reduce America's planet-warming greenhouse gas emissions 26 percent by 2025, from their levels in 2005.
It was unclear how, exactly, that submission to the United Nations would take place. Christiana Figueres, a former top United Nations climate official, said there was currently no formal mechanism for entities that were not countries to be full parties to the Paris accord.
Ms. Figueres, who described the Trump administration's decision to withdraw as a "vacuous political melodrama," said the American government was required to continue reporting its emissions to the United Nations because a formal withdrawal would not take place for several years.
But Ms. Figueres, the executive secretary of the United Nations Framework Convention on Climate Change until last year, said the Bloomberg group's submission could be included in future reports the United Nations compiled on the progress made by the signatories of the Paris deal.
There are 195 countries committed to reducing their greenhouse gas emissions as part of the 2015 agreement.
Still, producing what Mr. Bloomberg described as a "parallel" pledge would indicate that leadership in the fight against climate change in the United States had shifted from the federal government to lower levels of government, academia and industry.
Mr. Bloomberg, a United Nations envoy on climate, is a political independent who has been among the critics of Mr. Trump's climate and energy policies.
Mayors of cities including Los Angeles, Atlanta and Salt Lake City have signed on — along with Pittsburgh, which Mr. Trump mentioned in his speech announcing the withdrawal — as have Hewlett-Packard, Mars and dozens of other companies.
Eighty-two presidents and chancellors of universities including Emory, Brandeis and Wesleyan are also participating, the organizers said.
Mr. Trump's plan to pull out of the Paris agreement was motivating more local and state governments, as well as businesses, to commit to the climate change fight, said Robert C. Orr, one of the architects of the 2015 Paris agreement as the United Nations secretary-general's lead climate adviser.
On Thursday, Gov. Jay Inslee of Washington, Gov. Andrew M. Cuomo of New York and Gov. Jerry Brown of California, all Democrats, said they were beginning a separate alliance of states committed to upholding the Paris accord.