Greta Thunberg responds to Steven Mnuchin mocking her at the World Economic Forum
via International Monetary Fund / Flickr and Streetsblog Denver / Flickr

Seventeen-year-old Swedish climate activist Greta Thunberg made a dramatic speech Tuesday at the World Economic Forum in Davos, Switzerland.

In her address, she called for a public and private sector divestment from fossil fuel companies

"Immediately end all fossil fuel subsidies and immediately and completely divest from fossil fuels. We don't want these things done by 2050, or 2030 or even 2021 — we want this done now," she said.

U.S. Treasury Secretary Steven Mnuchin mocked the teenager on Thursday during a press briefing in Davos.

"Greta Thunberg has called for a public and private sector divestment from fossil fuel companies. Does that pose a threat to US economic growth?" a reporter asked Mnuchin.

"Is she the chief economist, or who is she? I'm confused," he replied. "It's a joke. After she goes and studies economics in college she can come back and explain that to us."

Mnuchin and his wife, Louise Linton. via Mike Licht / Flickr

In the climate debate the degrees we should really be concerned with are in Fahrenheit and Celsius. Specifically, 1.5 degrees Celsius. If the planet warms much more than that, the planet will be in major distress.

Over 400 million people will live in drought, the Arctic will have a 10 times greater chance of being ice-free in the summer, and up to 80 million people will be exposed to flooding.

Thunberg responded to Mnuchin's jibe with some basic facts that don't require a degree to understand.

"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," Thunberg tweeted.

"So either you tell us how to achieve this mitigation or explain to future generations and those already affected by the climate emergency why we should abandon our climate commitments," she added.

Mnuchin hasn't said much about climate change throughout his career, but it's clear he doesn't know what's happening. An exchange he had with Democratic Representative Sean Casten revealed how little he knows about the subject.

"I have expertise on many issues, climate is not one of them," Mnuchin admitted. "Outside of the United States there are some areas where climate issues are very, very, very significant. Climate issues are very significant. I think the U.S has made a lot of progress on this."

To his astonishment, Casten replied, "No we haven't. We are not on a sustainable path."

To say that there are climate issues "outside of the United States" assumes that this is an isolated issue that only affects certain regions. What happens in the U.S. affects people throughout the world and the actions that happen across the globe affect us at home.

It seems that Mnuchin is the one who needs to study up, not Thunberg.