"After She Studies Economics ...": US Treasury Chief's Jibe At Greta Thunberg

Just as the spat between U.S. President Donald Trump and Greta Thunberg seemed to be subsiding, US Treasury Secretary Steven Mnuchin took a new dig at the climate activist on Thursday.

Asked about Thunberg's call to divest from fossil fuels, Mnuchin told a news briefing: "Is she the chief economist? I'm confused ... After she goes and studies economics in college, she can come back and explain that to us."

Mnuchin's quip came two days after Trump and Thunberg sparred indirectly at the World Economic Forum in the Swiss ski resort of Davos. After Trump said the U.S. had committed to joining the one trillion tree initiative, Thunberg retorted that fixing the climate crisis was not only about trees.

Before he left Davos, however, Trump seemed to extend an olive branch, saying he wished he had seen Thunberg speak.

Addressing the Trump administration's stance on climate, Mnuchin said the U.S. position had been "misunderstood."

"There is a real misinterpretation of the U.S. policy. Let me be very clear: President Trump absolutely believes in clean air and clean water and having a clean environment."

Mnuchin later told CNBC he did not believe there were just a few years left to prevent a climate catastrophe.

"There are a lot of other important issues" threatening civilization, he said, citing health and nuclear proliferation.

"I think that the youth needs to understand: climate is one issue that needs to be put in contexts with lots of other things."

But German Chancellor Angela Merkel rushed to Thunberg's defence, saying that attaining the goals of the Paris climate accord, which the U.S. has quit, was vital.

"Time is pressing, so we - the older ones, I am 65 years old - must make sure that we take the impatience of young people positively and constructively," Merkel said in her speech to the WEF's annual meeting.