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Bill Nye, renowned scientist and television personality, speaks onstage during National Geographic Channel's "American Genius" panel at the 2015 Winter Television Critics Association press tour in 2015 in Pasadena, California. Getty Images

Bill Nye the Science Guy knows '90s kids. And he thinks they won't vote Republican unless GOP presidential candidates acknowledge the reality of climate change.

Nye, speaking this week on Comedy Central's "The Nightly Show with Larry Wilmore," urged reporters and viewers to think critically about climate change, which he called "a global issue we should all be concerned about." When talk turned to the November election, Nye said he was dismayed that leading GOP candidates Donald Trump and Texas Sen. Ted Cruz doubted climate change — but predicted they'll shift their stances after the Republican National Convention to cater to youth.

“Don’t be surprised if, after the.... Republicans pick somebody, this person goes, 'Well, I’ve been thinking about it and climate change is a big issue,'" Nye said. "Because I don’t think the party can quite get enough votes without millennials. Climate denial is almost entirely generational. Only now and then do you meet a young person — nobody your age is a climate denier. Very few. It’s all old people.”

The Nightly Show with Larry Wilmore
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The polls seem to back up his argument. The Harvard Institute of Politics found last April that 75 percent of 18- to 29-year-olds agreed that global warming was a proven fact, though 43 percent of them said they did not believe it was caused by human activities like car emissions. A Yik Yak poll from December, when many parts of the United States experienced warmer-than-normal winter temperatures, showed 70 percent were worried about climate change, according to Reuters.

"It is clear from our research not only that millennials accept the science of climate change but also that a candidate who does not is at a disadvantage," NextGenClimate, an environmental advocacy group, wrote in a news release.

Trump has called "a lot of" climate change a hoax, while Cruz has said it's a "pseudo-scientific theory." Ohio Gov. John Kasich, who is trailing behind both candidates, “believes that climate change is real and that human activity contributes to it," his spokesman Rob Nichols told the New York Times last year.