A decision by President Trump to pull the US out of the world's first comprehensive agreement on tackling climate change and seek renegotiated terms "fair" to America has drawn widespread international condemnation.
But Mr Bloomberg, currently the United Nations special envoy for cities and climate change, said work would continue to reduce emissions despite Mr Trump's statement.
He said: "The US will meet our Paris commitment and through a partnership among American cities, states, and businesses, we will seek to remain part of the Paris Agreement process.
"The American government may have pulled out of the agreement, but the American people remain committed to it - and we will meet our targets.
"Americans don't need Washington to meet our Paris commitment and Americans are not going to let Washington stand in the way of fulfilling it.
"That's the message mayors, governors, and business leaders all across the US have been sending."
The Paris accord commits countries to holding global temperature rises to "well below" 2C above pre-industrial levels, which will require global emissions to be cut to net zero by the second half of the century.
Scientists have warned failure to curb dangerous climate change will lead to sea level rises, more intense storms and flooding, more extreme droughts, water shortages and heatwaves as well as massive loss of wildlife and reduction in crop yields, potentially sparking conflict and mass migration.
Despite the decision by the US, the second biggest polluter after China, to pull out of the deal, many analysts suggest the shift to a low-carbon economy is now unstoppable, with renewable prices tumbling and new clean technology being developed and deployed.
Mr Trump's decision prompted criticism from many US business leaders, including clean tech entrepreneur and Tesla chief executive Elon Musk and Robert Iger, chief executive of the Walt Disney Company, who said they had resigned from the president's advisory council over the issue.
Announcing his decision on Thursday, Mr Trump claimed the Paris deal allows countries such as China and India to carry on polluting at the expense of the US economy and jobs.
He said the US would stop implementing measures to meet its commitments under the agreement to cut emissions by 26-28% on 2005 levels by 2025, and end funding for poor countries to cope with climate change.
In a press conference after a summit between the EU and China, European council president Donald Tusk said the bloc was stepping up co-operation with China on climate change.
"Which means that today, China and Europe have demonstrated solidarity with future generations and responsibility for the whole planet," he said.
He said the US decision to leave the Paris Agreement was a "big mistake", bigger than its failure to ratify the previous international climate deal, the Kyoto Protocol, because the new agreement - which covers all countries - was fairer.
"But the fight against climate change, and all the research, innovation and technological progress it will bring, will continue, with or without the US," he said.
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