YURI GRIPAS/Reuters

Rep. Alexandria Ocasio-Cortez sprung to Greta Thunberg's defense after Treasury Secretary Steven Mnuchin said on Thursday the teenage activist should study economics before lecturing the US on climate change.

"If you don't have an economics degree like Greta, they'll mock you for not having one," the Democratic congresswoman and Green New Deal proponent tweeted.

"If you DO have one, as I do, they'll claim it's illegitimate," she added. "Haters gonna hate & deniers will deny."

Thunberg also fired back at Mnuchin, saying, "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."

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Rep. Alexandria Ocasio-Cortez sprung to Greta Thunberg's defense after Treasury Secretary Steven Mnuchin said the teenage activist should study economics before lecturing the US on climate change.

"If you don't have an economics degree like Greta, they'll mock you for not having one," the Democratic congresswoman tweeted. "If you DO have one, as I do, they'll claim it's illegitimate."

"Haters gonna hate & deniers will deny," she added. "They will deny logic, science, and environmental consensus in order to protect oligarchy."

Ocasio-Cortez is a leading proponent of the Green New Deal, a sweeping set of legislation intended to combat economic inequality and climate change. Her latest tweet came after Mnuchin dismissed Thunberg as unqualified to weigh in on US environmental policy at a press conference on Thursday at the World Economic Forum in Davos, Switzerland.

"Is she the chief economist or who is she? I'm confused," Mnuchin jokingly replied to a question about the Swedish 17-year-old's call for America to immediately transition away from fossil fuels.

"After she goes and studies economics in college, she can come back and explain that to us," he added.

Thunberg fired back herself on Twitter, saying, "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."

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