New London — Connecticut College may join 15 other colleges in a grass-roots movement calling for policymakers to institute a tax on carbon dioxide emissions designed to spur growth of renewable energy and combat climate change.

The effort was launched publicly on Thursday, when about 200 people gathered for the airing of an episode of the National Geographic Channel series “Years of Living Dangerously” and a discussion with the creators of the Emmy-winning documentary, Joel Bach and David Gelber. Bach and Gelber have partnered with the group Our Climate to get colleges and other groups to sign carbon tax endorsement letters.

“This episode is about the relationship between climate change and mass extinctions in Africa, and the movement to put a price on carbon,” said Jane Dawson, director of the Niering Center for the Environment at Conn, in introducing the program. She invited the audience of about 200 people to sign a petition advocating for the tax, which already had collected more than 300 signatures since it began circulating on campus earlier in the week.

The petition calls on the Conn administration to join institutions including Vassar and Wesleyan in declaring the college’s support for the carbon tax, a market-based mechanism initiated by six U.S. states and more than a half-dozen countries, including Canada, to combat climate change. It is a solution being promoted by Bach and Gelber, former “60 Minutes” producers who launched the National Geographic series in 2014 out of a realization that the planet and humanity are in what they call "a race against time” to reverse a global catastrophe.

“If we can create a grass-roots movement to price carbon, we have a shot,” said Gelber, likening the strategy to taxes on cigarettes as a means of reducing smoking. “We are already late to this. But if we can accelerate the transition from dirty to clean energy, that’s what can save us.”

Under one proposal for a carbon tax plan, companies that extract or import coal, oil and natural gas would pay $40 per ton, a price calculated to cover the pollution and public health impacts of burning those fossil fuels, Gelber explained. The tax evens the playing field by making the price of renewable energy more competitive.

“You pay when it comes out of the ground,” Bach added.

The funds then could be returned to taxpayers as a rebate, rather than kept as a new source of government revenue. Taxpayers would receive the rebates regardless of whether they use fossil fuels or renewable energy.

As a result, Bach and Gelber explained, energy producers and consumers would have a financial incentive to switch to renewables and a “green economy” would flourish. They held up a carbon tax instituted eight years ago in Vancouver, British Columbia, as a model of how it could work and the positive effects.

“So many times, people ask what they can do about climate change,” Bach said. “So many people are saying this is a solution. This can be scaled up. Our role is to try and make as many people aware of this as possible.”

Bach and Gelber are hoping to help spur a wave of support for a carbon tax in local communities, states and colleges that will percolate up to Congress and the White House. Group actions, they said, rather than individual efforts, are what’s most needed.

“It’s people getting together in institutional forums, in some kind of organized way,” Gelber said.

Bach also urged the audience to use their voices.

“What you can do is keep sharing the story of climate change,” he said. “Share it with everyone you know.”

Jamie Whitman, who is leading climate change activities for the activist group Rise Up Mystic, asked how to get more people engaged in the pushing for climate change solutions, particularly those who are most vulnerable to the effects of the floods, droughts and new diseases being unleashed as a result.

“How are we reaching out to those people who are marginalized, who have less of a voice?” she asked.

Bach said the series has focused episodes on showing how climate change already is impacting the world’s most impoverished communities, and stressed that “the world is already putting two and two together” in recognizing that countries like the United States and China that consume the most fossil fuel are the main source of the problem. This, he said, is feeding resentment and radicalism in impoverished countries toward wealthier nations. Even in this country, he said, poor communities are the most vulnerable.

“We’ve really tried to tell the story of the underrepresented ones, who are going to feel the worst impacts,” he said.

Now preparing for the series’ third season, Bach and Gelber said they will continue using the appeal of celebrities as well as the voices of youth to try to reach a broad audience with a difficult story. In the episode shown Thursday, actress Nikki Reed and “Daily Show” comedian Aasif Mandvi narrated explanatory segments about the carbon tax movement and iconic African animals such as elephants and hippopotamuses facing extinction in the coming decades as the environment they depend on turns barren.

Humans will not be immune to a similar fate, experts in the show say. Mandvi peppered his sobering segments with self-deprecating humor, while Reed paired up with inspiring young climate activists and “stand-up economist” and comedian Yoram Bauman for an accessible description of the carbon tax.

“They make it watchable, because it’s so depressing,” Bach said.

j.benson@theday.com