U.S. Treasury Secretary Steven Mnuchin mocked 17-year-old climate activist Greta Thunberg on Thursday, after she called on investors to pull their funds from fossil fuel companies. Speaking to reporters at the World Economic Forum in Davos, Switzerland, Mnuchin said of Thunberg, “After she goes and studies economics in college, she can go back and explain that to us.” Mnuchin’s comments sparked a torrent of replies across social media from economists who rushed to Thunberg’s defense. Thunberg responded on Twitter writing, “My gap year ends in August, but it doesn’t take a college degree in economics to realise that our remaining 1,5° carbon budget and ongoing fossil fuel subsidies and investments don’t add up.”