Vice President Kamala Harris’ appeal to moderate voters included concessions on climate change, including her flip-flopping in support of fracking after pledging in 2019 to ban it. Former President Donald Trump, meanwhile, has said he wants clean air and clean water, but denies the science of climate change and threatened to claw back unused federal funds from a Biden administration climate bill to accelerate the clean energy transition.

But for the most part, the problem is ignored.

“It’s incredibly disheartening,” said Jennifer Rushlow, a professor of environmental law at Vermont Law and Graduate School, who said she’s disappointed climate change isn’t playing a more prominent role. She is not alone. Climate advocates in the region said they wish the issue resonated more strongly, but are not surprised the candidates are focusing on the economy instead.

Some suggest Harris is avoiding the topic because it could alienate moderate voters. “There’s an incredibly stark choice” when it comes to climate change, said Paul Bledsoe, an assistant professor at American University’s Department of Public Administration and Policy. “Perhaps given Trump’s climate nihilism, voters already believe there is such a profound difference that there isn’t much incentive for either candidate to talk about it.”

Some environmental advocates say they largely agree with Harris’s approach, especially given that The Biden administration track record, which includes incentives to boost clean energy production as part of the Inflation Relief Act. They say they accept the need to do whatever it takes to defeat Trump.

“Politicians don’t talk about climate change because they don’t poll well, not because it’s not important,” said Johanna Neumann, senior director at the nonprofit Environment America.

When the Pew Research Center polled voters In terms of the issues they thought were very important, climate change came in last — followed by the economy, health care, Supreme Court appointments and six other options. Likewise in a Globe/Suffolk university poll of 500 likely Massachusetts votersonly 3.6% said climate change was the most important issue driving their vote.

That doesn’t mean voters don’t care about it. One poll on voter attitudes about climate change by Yale University and George Mason University this spring, 62 percent said they preferred candidates who supported action on global warming.

There are deep partisan divisions, however: 97 percent of liberal Democrats and 81 percent of moderate Democrats prefer candidates who favor action on climate change, compared to 47 percent of moderate Republicans and just 17 percent of conservative Republicans.

Anthony Leiserowitz, director of Yale’s program on climate change communication, said he was “mystified” that climate change is not playing a bigger role in Harris’ presidential campaign, given these political divisions. It’s an issue that, based on polls, the Democratic base cares deeply about — and thus could motivate them to show up on Election Day.

“These are people you don’t need to convince that climate change is a serious problem. You just have to get them to show up and vote,” Leiserowitz said.

This is the approach they take The Environmental Voter Projecta Boston-based nonprofit that uses data to identify the millions of voters who are likely to go to the polls but who would prioritize climate change if they did vote.

In this election, the group identified 4.8 million potential first-time climate voters in 19 states, meaning they are registered but haven’t voted in 2020 or since and, based on the analysis, are likely to prioritize voting environment. As a group, they are disproportionately young, so climate change has the potential to drive a large bloc of new voters in one direction.

“We never talk about climate change,” said Nathaniel Stinnett, executive director of the Environmental Voter Project. Instead, they knock on doors, make phone calls, send emails and more – anything to get climate-conscious voters to show up and cast their ballots.

In Massachusetts, the Environmental Voter Project identified 246,361 potential first-time voters. So far, about 12,000 have voted. In some swing states, the numbers are higher. Some 33,521 first-time climate voters have already cast ballots in Georgia, as have 20,930 in North Carolina.

Stinnett stressed that early voting data is not predictive of final results, but said he feels positive.

“None of these people needed to vote – this data is not just interesting, it’s extraordinary,” he said. “We live in a time of absurdly close elections, where fewer than 12,000 voters decided both Georgia and Arizona four years ago. So the fact that 33,000 first-time climate voters have already voted in Georgia is incredibly exciting.”

The Sunrise Movement, a youth-led group that supports policies that mitigate climate change, is also using global warming to motivate voters, even if the leading candidates are not.

“The climate is on the ballot,” said Kidus Girma, campaign director for the Sunrise Movement. “It comes up constantly in our conversations with young people, whether they’re talking about the jobs they want, the temperatures they’re experiencing in their communities or the future they’re looking for.”

That demographic — young voters — tends to rate climate change as an important issue, said Peter Haas, a political science professor at the University of Massachusetts Boston, but that’s unlikely to get candidates to talk about it.

“There’s the recurring question: Are younger voters really turning out?” said Haas, who studied environmental policy. “They can think what they want, but if it’s unlikely to pan out, candidates aren’t going to spend time trying to court them.”

As of Tuesday, Sunrise reported reaching more than 1.9 million young voters in several swing states.

But as groups like Sunrise and the Environmental Voter Project race to get climate voters to the polls, advocates are left looking inward, wondering how climate slipped off the radar of priority issues.

“The truth is we need to build more public support for renewable energy and for keeping fossil fuels in the ground,” said Environment America’s Neumann. “And until we do that, political leaders will continue to read the tea leaves and go where the public is.”

Sabrina Shankman can be reached at [email protected]. Follow a @shankman. Erin Douglas can be reached at [email protected]. Follow a @erinmdouglas23.