US TREASURY Secretary Steven Mnuchin took a swipe at teenage climate activist Greta Thunberg today, saying that she is not qualified to give advice on climate change.

During a press briefing at the World Economic Forum in Davos, Switzerland, Mr Mnuchin dismissed the 17-year-old’s suggestion that governments and companies need to cut back dramatically on their use of fossil fuels.

When asked how such measures would affect the US economic model, Mr Mnuchin said: “Is she the chief economist? Who is she? I’m confused.” Following a brief pause, he said his comment was “a joke.”

“After she goes and studies economics in college, she can come back and explain that to us,” he said.

Ms Thunberg, who has become an international role model for climate activists, responded by tweeting: “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.”

She has been a vocal critic of US environmental policy, particularly President Donald Trump’s decision to pull the country out of the Paris Agreement on limiting climate change.

Mr Trump said on Tuesday that he doesn’t “really know anything about her,” but last month tweeted that Ms Thunberg should “chill” and “work on her anger management problem, then go to a good old fashioned movie with a friend!”

Mr Trump’s ire came after Ms Thunberg was named Time magazine’s Person of the Year for beginning the global climate strike movement.

The climate activist responded by changing her Twitter description to “confirm” that she was carrying out Mr Trump’s suggestions.