Treasury Secretary Steve Mnuchin becomes the most recent member of the Trump admin to party climate activist Greta Thunberg, condescendingly telling the 17-year old to study economics in school prior to speaking.

Treasury Secretary Steven Mnuchin, 57, promised not to know who Greta Thunberg is before insulting her in the World Economic Forum. The former film manufacturer lashed out in the 17-year-old climate activist later she gave impassioned speech urging business leaders to quit investing in fossil fuels instantly. “Is she the chief economist? Who’s she, I am perplexed. After she belongs and studies economics at school she is able to return and explain that for people,” Mnuchin stated at a media conference during the yearly event in Davos, Switzerland. He added after a pause he was just”joking.”

Thunberg, whose tireless activism obtained her called TIME’s Person of the Year 2019, told world leaders in the summit their inaction on climate change could condemn their kids to inevitable environmental disaster. “I wonder, what would you tell your kids was the motive to neglect and leave them facing the climate chaos you brought upon them” Thunberg told a quiet area on January 22. “Our property is still on fire. Your inaction is fueling the fires from the summertime. We’re telling you to fear, and also to behave like you loved your kids above all else” she added, echoing the potent speech she gave 2019 World Economic Forum. Thunberg’s Davos speech came soon after US President Donald Trump‘s, where he assaulted climate activists as”heirs of yesterday idiotic fortune tellers.”

Thunberg was at the sixth row since he talked, calling activists for example himself”perennial prophets of despair” and mocked what he called”their forecasts of the apocalypse.” Trump claimed he was a”big believer” in the surroundings, and vowed for the United States to join the UN’s Trillion Tree Campaign. Thunberg didn’t mention Trump within their speech, but stated that planting trees had been”great, but nowhere near enough”

Mnuchin defended the United States’ environmental policies Davos following his quip about Thunberg, stating that Trump”absolutely” believes in”clean water and air, and a clean environment” America and China would be the world’s largest emitters of greenhouse gases.