One of the Donald Trump's well-reported whoppers in tonight's presidential debate concerned climate change.

It came when Democrat Hillary Clinton pointed out that Trump has previously claimed that global warming is a hoax perpetrated by the Chinese.

To that Trump responded: "I did not say that."

In fact, he tweeted precisely that, along with many other messages suggesting that he doesn't believe that human activity is contributing to climate change.

Trump's denial of his global warming denial prompted the director of 350.org, May Boeve, to accuse him of "just talking climate crazy".

“Climate change took its rightful place as an important campaign issue during this debate thanks to Secretary Clinton," Boeve said in a statement distributed this evening. "She made a strong push for climate action, while Trump tried to dodge his previous statements about global warming being a hoax created by the Chinese. Clinton knows that climate is a winning issue that can turn out voters this November, and a key to jobs and prosperity in the years to come."