Image copyright AFP The US secretary of state John Kerry says __that the overwhelming majority of US citizens support the US taking action on climate change.
Speaking at a meeting in Marrakech, Mr Kerry said he believed __that US commitments would not be reversed.
President-elect Donald Trump has vowed to pull the US out of the Paris Climate Agreement once in office.
Mr Kerry said that market forces, rather than policy, would ensure a transition to a low carbon world.
He played an important role in building agreement with China on how the two leading economies could reduce their emissions. He was one of the architects of the Paris Climate Agreement last December.
Speaking in his last climate conference as Secretary of State, Mr Kerry delivered a passionate and emotive defence of the global effort to tackle climate change.
Massive progress was being made, he said. Investments in renewables were booming and the trend to decarbonise the world's energy supplies was irreversible.
Analysis - David Shukman, Science Editor
There was a catch in John Kerry's throat as he recalled taking his granddaughter to the signing of the Paris Agreement earlier this year.
It was the only hint of the pain that must accompany the US Secretary of State's final months in office. He has toiled towards the goal of an international deal on climate change. I recall his jovial determination in an interview a decade ago in the Polish city of Poznan. His message back then was one of optimism that the world could act together.
And, sure enough, a very long journey later, Mr Kerry was there at the tumultuous moment when the Paris Agreement was reached last December. Now one can only guess at his sense of uncertainty, and maybe loss as well, as Donald Trump approaches the White House.
His tone, though, was upbeat: the world has come too far, he argued, for any reversal now. But the coming months will show what's in store for a legacy that took so much effort to achieve.
Climate reality
Americans, he said, believed in the reality of a warming planet - and they would stand behind the carbon-cutting promises the country had made in the Paris deal.
"No-one... no-one should doubt the overwhelming majority of the citizens of the United States, who know climate change is happening and who are determined to keep our commitments that were made in Paris," Mr Kerry said to a strong applause.
Mr Kerry pointed to research showing that investments in renewable energy in 2015 were around $350bn, some six times larger than they were in 2014. In the US, wind powered electricity had tripled, while solar power had grown by over 30 times.
These marketplace investments wouldn't be stopped, he said, by a change in leadership in the White House.
"I can tell you with confidence that the United States is right now, today, on our way to meeting all of the international targets that we have set, and because of the market decisions that are being made, I do not believe that that can or will be reversed," he continued.
The Secretary of State didn't mention Mr Trump directly and didn't offer any direct comment on the President-elect's plans to take the US out of the Paris Agreement. But he said that investing in coal, something that Mr Trump is very keen on, would be a disastrous move for the planet.
Back slapping
"We literally can't use one hand to pat ourselves on the back for what we have done to take steps to address climate change, and then turn around and use the other hand to write a big fat cheque enabling the widespread development of the dirtiest source of fuel in an outdated way, it just doesn't make sense. That's suicide, and that's how we all lose this fight," Mr Kerry said.
Meanwhile, the chorus of voices calling on President-elect Trump to keep the US in the Paris agreement continued to grow.
Here in Marrakech, representatives of more that 360 US businesses released a statement supporting the deal and asking global leaders to accelerate the transition to a low-carbon economy.
The diverse group includes DuPont, Gap, General Mills, Nike, Mars, Kellogg Company among other major companies.
"Now, more than ever, Levi Strauss & Co believes it is important to reaffirm our commitment to address climate change by supporting the Paris Climate Agreement," said Michael Kobori, from the company.
Mr Kerry's speech wasn't the only action taken by the US government here to emphasise the current administration's commitment to cutting carbon.
The US has lodged with the UN their plan for reducing their carbon emissions by 2050. It calls for an 80% cut in CO2 from 2005 levels via a much bigger role for renewables in energy production and the continued use of fossil fuels only with technology to capture carbon.
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