It seemed like a preposterous idea as we gathered along the sofas of my living room last summer.

Could we really pull off a candidate forum specifically about climate change, in a congressional district held by Republicans since George H.W. Bush and home to more of the oil and gas industry than just about anywhere in the country?

Having lived in the Seventh Congressional District of Texas for more than a decade, I can't remember giving any thought to its Democratic primary. This time, though, seven Democrats are vying to challenge nine-term Congressman John Culberson. After Hillary Clinton narrowly carried it in 2016, the Cook Political Report rates our perennially Republican congressional district a "toss-up."

That our organizations could even come together for that summertime meeting was itself a sign of the times. Sure, Houston chapter of the 350.org climate advocacy organization had been around for years. But Pantsuit Republic Houston — Climate and Environmental Racism Committee, Indivisible To Flip TX7 and Texans for Climate Change Action, a student group which I help advise, were all founded in response to the 2016 election.

But none of us had ever planned a candidate climate forum. And we had more than a bit of skepticism about whether candidates would be willing to speak out on a controversial topic and how many voters would care enough to listen.

But recent surveys debunk the misperceptions of voter apathy on climate. A survey by Harvard and Politico showed that Democrats rank climate change neck-and-neck with healthcare and Trump-Russia allegations as the top issues motivating their vote in 2018. Another survey showed that even most Republicans wanted President Trump to remain in the Paris Climate Agreement. That's why I've asserted climate action could be an issue that motivates Democrats without alienating Republicans.

So we plowed ahead with our plans. And, sure enough, all the Democratic candidates agreed to participate. Congressman Culberson's office declined our invitation.

Registrations quickly topped the capacity of the Rice University lecture hall we had originally reserved. The administration of West University Elementary School graciously offered their larger space, where more than 400 people attended the forum this past Saturday.

Congressman Beto O'Rourke kicked off our event while receiving an award from Environment Texas.

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On a national level, the Trump administration has pushed for "red team, blue team" debates of whether to accept climate science. That wasn't our aim last weekend. As an atmospheric scientist and moderator of the forum, I made clear that we would not waste our time debating established science or whether climate change is a Chinese hoax.

Instead, we focused on the challenges of slowing global warming and adapting to the impacts it's causing locally in Houston and beyond. Only by accepting the science of climate change can we get to the more interesting discussions of what to do about it.

The discussion revealed a lot of common ground, but also distinctions. All the candidates want more federal funding to recover from Hurricane Harvey and prepare for storms to come. And there was general agreement on the need to accelerate the transition to wind and solar power, clean up air pollution and provide commuters with alternatives to driving alone in gas-guzzling cars.

The differences emerged on how to address emissions from fossil fuels. Several candidates supported putting a price on pollution via a carbon tax, as has been endorsed by everyone from the Citizens Climate Lobby to the Climate Leadership Council backed by ExxonMobil and former Secretary of State James Baker. Others backed a cap-and-trade system or were noncommittal on their approach. Voters got to see distinctions emerge in a primary in which commonalities have far outweighed differences on policy positions.

But the true value of the event might come less from what the voters learned about the candidates than from what the candidates learned from the voters. Simply put: We care. That message rang through loud and clear, from the 400 voters who showed up on a rainy Saturday afternoon to the thousands more who have watched the Facebook Live video online.

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When voters care, candidates respond. At the first candidate forum I attended last year, I cringed at the nonsensical response I got to my question about climate. This time, asking seven more challenging questions to seven candidates, I found almost all the responses to be thoughtful and well informed.

As a professor, I could tell the candidates had done their homework. They couldn't bluff their way to an easy A with voters who cared.

Whoever is elected to Congress this November, they'll know there's a motivated contingent of voters eager to see a more vigorous federal response to climate. And if we've shown that to be true in the oil patch of a red state, perhaps similar events elsewhere could provide a wake-up call to other representatives as well.

Daniel Cohan is an associate professor in the Department of Civil and Environmental Engineering at Rice University.

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