03:50 - Source: CNN
Sanders: Where was Clinton on progressive issues?

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Bernie Sanders was asked by a high school student about the science behind global warming

"It is already causing devastating problems in our country and the world," he responded. "That is what the scientists are saying"

Des Moines, Iowa CNN —  

Bernie Sanders has made fighting climate change a central part of his message, and he’s not about to hold back when challenged by someone who questions the scientific consensus that human-caused emissions are behind global warming – even if it’s a teenager.

The Vermont senator, old enough to be the grandfather to many of the attendees at a town hall at Roosevelt High School Thursday, was asked by a 17-year-old about his position on climate change. She said that she was not convinced it was caused by humans.

“I haven’t seen any actual scientific evidence that global warming is actually happening,” she said. “It’s only very recent. So I’d like to know why you think it’s happening.”

Sanders respond with a polite but firm: “You’re wrong.”

“It is already causing devastating problems in our country and the world. That is what the scientists are saying,” he told her.

Sanders often speaks of the need to address greenhouse gas emissions and global warming, and has used his early advocacy on the issue – including his long-time opposition to the Keystone XL Pipeline – to appeal to liberals in his bid against Hillary Clinton.

The senator added that he applauded the young woman for vocalizing her opinion, noting the skepticism of climate change is shared by millions of Americans.

“And I thank you for standing up, I thank you very much for asking because this is the kind of debate that we have, there are millions of people who agree with you,” he told her.

“So I appreciate your point of view,” he later added, “but I absolutely believe that climate change is real, it is caused by human activity, and we need to transform our energy system away from fossil fuel to energy efficiency and sustainable energy.”

The exchange was part of a 45-minute appearance for Sanders at Roosevelt High.