“We are in the beginning of a mass extinction, and all you can talk about is money and fairy tales of eternal economic growth,” said activist Greta Thunberg, speaking at the United Nations yesterday. “How dare you?”

“Marketplace” host Kai Ryssdal asked Ashoka Mody, professor of international economic policy at Princeton, what he thought of Thunberg’s speech.

“I think she is cutting out a political path on which economists must now travel,” Mody told Ryssdal. However, said Mody, economic growth itself is not the issue.

“We need to change the way we do things,” he said. “It requires a much more intrusive environmental regulation on the premise that that regulation will create a new avenue for innovation and investment.”

Click the audio player above to hear the interview.