Trump spent his night making fun of teen activist Greta Thunberg

Donald Trump spent Monday night working. Oh my god, kidding! He was up until midnight tweeting sarcastic comments about Greta Thunberg.

Thunberg, a 16-year-old climate activist, delivered an emotional, now-viral speech at the U.N. Climate Summit on Monday, admonishing world leaders for failing to take appropriate action on climate change. Trump, who has called climate change a "hoax" and is likely in search of a way to distract constituents from the growing Ukraine scandal, then trashed the address the only way he knows how: tweeting something ill-advised and offensive.

"[Thunberg] seems like a very happy young girl looking forward to a bright and wonderful future," he wrote. "So nice to see!"

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The clip attached to Trump's tweet highlighted a particularly bleak portion of Thunberg's remarks. "People are suffering, people are dying, entire ecosystems are collapsing," she said. "We are in the beginning of a mass extinction, and all you can talk about is money and fairy tales of eternal economic growth.”

Trump's tweet came hours after Michael Knowles, who works for the conservative website The Daily Wire, called Thunberg a "mentally ill child" on Fox News. Knowles was quickly admonished by commentator Chris Hahn, who was also on the segment.

After arriving in New York City last August, Thunberg addressed the often bigoted criticism she receives from the right, particularly about her Asperger's syndrome.

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"When haters go after your looks and differences, it means they have nowhere left to go. And then you know you’re winning!" she wrote.

Seems like ... she's winning.

UPDATE: Sept. 24, 2019, 12:34 p.m. EDT Thunberg updated her Twitter bio on Tuesday to Trump's quote about her.