Greta Thunberg may have leveled a “death stare” at President Trump and other leaders, as the news media characterized it, when the 16-year-old addressed a U.N. climate summit earlier this year. But no words have been exchanged between the world-famous activist and the leader of the world’s largest economy, who has recently delivered on his promise to pull the U.S. from the multinational Paris climate accord.

“ ‘Honestly, I don’t think I would have said anything because obviously he’s not listening to scientists and experts, so why would he listen to me? So I probably wouldn’t have said anything, I wouldn’t have wasted my time.’ ”

Thunberg said during a guest-editor spot on a BBC program that it wasn’t worth her breath.

When Thunberg was named Time’s “Person of the Year” for turning a solo climate-change protest in front of Swedish parliament into repeat global walkouts by millions in roughly a year, Trump — presumed to be on the short list for the coveted cover — tweeted she should work on her “anger management” and maybe catch a movie with a friend.

Read:Trump didn’t win Time’s ‘Person of the Year,’ so he mocks the teen who did

In addition to the magazine honor, the teen’s following and ability to engage with several global leaders just earned commendation from renowned naturalist and broadcaster David Attenborough as they connected via Skype for the radio program.

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Thunberg told Sir David how he inspired her activism. He in turn told Thunberg she had “achieved things that many of us who have been working on the issue for 20 years have failed to do.” He added that the teen was the “only reason” that climate change became a key topic in the recent U.K. general election.

Read: How Greta Thunberg and ‘flygskam’ are shaking the global airline industry

The BBC also interviewed Thunberg’s father Svante who said his daughter, who has been diagnosed with autism-related Asperger syndrome, appears to have emerged from depression since becoming an activist, though he still worries about the “hate” she faces. Her father said he was particularly worried about “the fake news, all the things that people try to fabricate [about] her — the hate that that generates” including from U.S. President Trump.

Read:Greta Thunberg has likened her Asperger syndrome to a ‘superpower’ — some Fortune 500 employers appear to agree

Trump has said he wants other big pollution emitters, including China, to do more work toward meeting the Paris agreement before the U.S. will comply with the voluntary action. He has rolled back several environmental regulations, citing among other things, their burden on the U.S.’s aim for energy independence.

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