The teen climate activist said she doesn't think the president would learn anything from her that he hasn't heard before

Talking to Donald Trump About Climate Change Would Be a 'Waste of Time,' Greta Thunberg Says

Greta Thunberg has plenty of messages for world leaders regarding climate change, but one person she will not be sitting down with to talk shop is President Donald Trump.

The Swedish climate activist, 16, said she has no interest in talking things through with Trump, who has repeatedly dismissed climate change and falsely claimed it was a hoax perpetuated by the Chinese, as she believes it would prove fruitless.

Get push notifications with news, features and more.

“I don’t understand why I would do that,” she said on The Ellen DeGeneres Show Friday. “I don’t see what I could tell him that he hasn’t already heard, and I just think it would be a waste of time, really.”

Trump, 73, and Thunberg previously shared a viral encounter at the U.N. Climate Action Summit in September, where she appeared to give him an icy stare-down as he walked by.

She later said, however, that the moment was based more in shock than anything else, as his appearance was unscheduled.

Image zoom Greta Thunberg, Donald Trump TIMOTHY A. CLARY/AFP/Getty; Win McNamee/Getty

“I was stopped because suddenly he came in and security went, ‘You have to step to the side.’ And I just wondered what was going on,” Thunberg told the Scandinavian talk show Skavlan. “And then he showed up. I think I was very shocked.”

At the same summit, Thunberg gave a fiery speech in which she blasted world leaders for showing more interest in making money than in saving the planet by reducing carbon emissions — a speech Trump later took note of.

The president retweeted a video of Thunberg speaking, adding on an apparently sarcastic message.

Image zoom Greta Thunberg, Ellen DeGeneres NBC

“She seems like a very happy young girl looking forward to a bright and wonderful future. So nice to see!” he wrote.

During her interview with Skavlan, Thunberg said she interpreted Trump’s words as sarcastic, but said that “of course” he would write something like that.

“I mean, you can interpret it in many different ways,” she said of his tweet. “But I mean, I knew that sometime he was probably going to say something about me. It was like, it doesn’t make any difference, in a way.”

RELATED VIDEO: Greta Thunberg Speaks at the Climate Action Summit in New York

Then in October, Trump retweeted and praised a Twitter user who criticized the speech and accused Thunberg of being an “actress.”

Thunberg previously sent a message that his words had little effect on her when she briefly changed her Twitter bio to reflect his initial tweet.

“A very happy young girl looking forward to a bright and wonderful future,” it read, according to screenshots, though she has since changed it once again.