The Prince of Wales “did most of the talking” during their meeting, according to President Trump, who said he “totally listened” to Charles when the issue of climate change came up.
Mr Trump has previously accused climate experts of having a “political agenda” and said “the concept of global warming was created by and for the Chinese in order to make US manufacturing non-competitive” in a now infamous 2012 tweet.
“I did mention a number of things. I did say the United States right now has among the cleanest climates.”
Asked if Charles moved him on the issue, Mr Trump said: “What moved me was his passion for future generations. He’s really not doing this for him, he’s doing this for future generations.
“This is real, he believes that. He wants to have a world that’s good for future generations and I do, too.
“He’s Prince Charles, he doesn’t have to worry about future generations unless he’s a very good person who cares about people, and that’s what impressed me, maybe the most.”
Before his state visit, hundreds of climate change experts urged Theresa May to confront Mr Trump over his approach to the issue.
A letter signed by 250 academics from universities and research bodies across the UK stated his refusal to tackle global warming was “increasing risks for lives and livelihoods” around the world.
One of Mr Trump’s first acts in office was to announce that he would pull the US out of the Paris climate agreements that commit many nations to take action to limit global temperatures to “well below 2C above pre-industrial levels".
A spokesperson for the UK Government said before Mr Trump’s visit: “The Prime Minister has raised climate change with the president before and will do so again during his visit.
“Tackling climate change is a priority for the UK. We are driving forward international action through our work at the UN and with our Commonwealth partners, and we’re proud to have offered to host COP26 (the UN climate summit in 2020).
“As the Prime Minister has said previously, we were disappointed by the US decision to withdraw from the Paris Agreement in 2017 and continue to hope they will return.”