If there was any doubt whether Donald Trump understands how climate change works, he completely erased it on Wednesday.

During his state visit to the U.K., the president sat down with Prince Charles, the heir to the British throne, and their meeting reportedly lasted 75 minutes longer than scheduled. The prince was trying to convince Trump that climate change is real. In recounting their exchange, Trump revealed some, um, gaps in his climate change knowledge.

“He is really into climate change, and I think that’s great,” Trump told Piers Morgan on “Good Morning Britain.” “What he really wants and what he really feels warmly about it is the future. He wants to make sure future generations have climate that is good climate, as opposed to a disaster, and I agree.”

A good climate, and not a bad climate. Noted, Mr. President.

“I did say, ‘Well, the United States right now has among the cleanest climates there are based on all statistics,’” the president added. “And it’s even getting better because I agree with that we want the best water, the cleanest water. It’s crystal clean, has to be crystal clean clear.”

To be crystal-clear: Pollutants that threaten the water supply are not greenhouse gases, which cause climate change. Curbing global heating requires the cutting of carbon emissions, which warm the planet. Trump pulled the U.S. out of the landmark Paris Agreement in 2017, and his administration is in the process of repealing the only federal regulation designed to curb carbon emissions from coal- and gas-fired power plants.

“What people want to hear from you on climate change is that you basically understand that almost every scientist who looks into this believes that climate change is a very real and present danger,” Morgan told Trump during the interview. “Do you accept that?”

Trump blamed a deteriorating climate on other countries, who “don’t do the responsibility,” as he said. “China, India, Russia, many other nations, they have not very good air, not very good water, and the sense of pollution and cleanliness.”

“In terms of a planet, we’re talking about a very small difference between China and the U.S. and other countries,” he added. Indeed, carbon emissions affect the global climate. But air pollution, of the variety that makes it harder to breathe, largely doesn’t.

“Do you personally believe in climate change?” Morgan asked.

“I believe there’s a change in weather, and I think it changes both ways,” he said. “Don’t forget, it used to be called global warming, that wasn’t working, then it was called climate change. Now it’s actually called extreme weather, because with extreme weather you can’t miss.”

No one is calling climate change “extreme weather,” though extreme weather events are way more likely as the world heats up.