Governors' Wind Energy Coalition

Supporters in in Manchester, N.H., cheer as Sen. Bernie Sanders (I-Vt.) after winning the New Hampshire primary on Tuesday. (Salwan Georges/The Washington Post)

Voters in the Granite State just cemented climate change as a major election issue — one that just helped vault both Bernie Sanders and Pete Buttigieg to the top of the race for the Democratic nomination.

One in 4 people who voted in the Democratic primary in New Hampshire on Tuesday said that climate change was the issue that mattered most to them, according to network exit poll results.

For Democratic voters, climate change ranked higher than income inequality and foreign policy — both more traditionally the fodder of presidential campaigns in past elections. The only issue of more concern was health care.

Once an electoral afterthought, the issue of rising global temperatures has rocketed in prominence in the race for the Democratic nomination amid dire headlines about how the world has just over a decade to get climate change under control.

Just how do Tuesday’s results compare to 2016? We don’t know. The exit poll four years ago didn’t even offer climate change as an option.

Concern about climate change shows no sign of going away in the 2020 race. Democratic caucus-goers in Iowa, who voted last week, ranked it as their second most important concern, again after health care. Potential voters in Nevada, which will hold a caucus on Feb. 22, also picked it as the No. 2 issue, according to a Suffolk/USA Today/Reno Gazette Journal poll in January.

Sanders, with about 26 percent of the vote, won the primary itself, beating Buttigieg by less than 2 points. But among those most concerned about climate change, the former mayor of South Bend, Ind. won a larger share of the vote (30 percent) than the senator from Vermont (22 percent).

The results show that Sanders and Buttigieg stand apart from the rest of the field in offering a message on climate change that resonates with progressive and moderate voters, respectively.

Pete Buttigieg receives hugs after he leaves the stage during the primary night rally in Nashua, N.H. (Bonnie Jo Mount/The Washington Post)

Though several other candidates have endorsed the Green New Deal, a manifesto calling for sweeping cuts to climate-warming emissions in the United States, it is Sanders alone who has emerged as its champion in the 2020 race.

Sanders has earned the endorsement of the Sunrise Movement and its swarm of volunteers who knocked on doors for him in New Hampshire. His supporters spontaneously started chanting “Green New Deal” at his victory rally Tuesday evening. In speech after speech, he has hammered “the greed of the fossil fuel industry,” as he said on the debate stage in Manchester on Friday.

But it was Buttigieg — with an emphasis on technocratic solutions — who lured more New Hampshire voters concerned about climate change.

Speaking in Concord last week, Buttigieg contrasted himself with Sanders on the issue. He reiterated his support for placing a price on carbon, a policy many economists say is the fastest and most efficient way to slash carbon emissions. Sanders once supported, but now opposes, a carbon tax.

And while the Vermont senator wants to shut down all current nuclear power plants over concerns about radioactive waste, Buttigieg made clear taking the largest source of carbon-free power offline would be a “meat cleaver solution.”

A response like that may have resonated in New Hampshire. The state gets more than half of its electricity from a single nuclear power reactor in Seabrook.

Emily Guskin, Dan Keating and Scott Clement contributed to this report.