In February 2015, a top Republican lawmaker tossed a snowball on the Senate floor in a cringeworthy stunt meant to illustrate his scientifically unfounded skepticism of climate change.

Nearly four years later, the White House is promoting the same brand of denialism and fealty to the fossil fuel industry at the United Nations’ climate conference in Poland. But in Washington the snowball metaphor might more accurately describe how a markedly different brand of climate politics is gaining support.

In barely a month, talk of a so-called Green New Deal ― a sweeping climate policy to simultaneously transition away from oil, gas and coal and ease widening income equality ― stormed from the fringes of policy debates into the political mainstream.

By Wednesday, the burgeoning effort to establish a select committee in the House of Representatives on a Green New Deal ― essentially a plan to make a plan ― picked up its strongest endorsements yet, netting support from the co-chairs of the 78-member Congressional Progressive Caucus and from the first labor union to back the proposal. At least 35 incoming or sitting House members support the resolution, as do four senators.

The proposal, championed by Rep.-elect Alexandria Ocasio-Cortez (D-N.Y.), came as grassroots groups like the Sunrise Movement and Justice Democrats organized protests at the Capitol, with young activists occupying Democratic leaders’ offices and urging lawmakers to pledge their support. Nearly 150 people were arrested Monday in the groups’ largest demonstration yet.

“The idea that we give special attention to climate change should be a no-brainer,” Rep. Mark Pocan (D-Wis.), a Progressive Caucus co-chair, said by phone Wednesday.

ASSOCIATED PRESS Activists with the Sunrise Movement, a grassroots youth-focused climate justice group, repeatedly occupied Democratic leaders' offices over the past month to demand a Green New Deal.

The resolution faced skepticism from the top Democrats on natural resources and energy committees that wield legislative power over the issues a Green New Deal would cover. But proponents tweaked language in the proposal this week to mandate the select committee to lay out a vision for a Green New Deal while maintaining existing committees’ authority over the lawmaking process.

“I wouldn’t even call it compromises. It was more specificities,” Pocan said. “It was really getting at making it specific and workable. We wanted to make it so it could be an executable idea.”

The resolution calls for barring lawmakers who have accepted donations from the fossil fuel industry from serving on the select committee. Maintaining legislative power for existing committees with members who might have taken contributions from oil, gas and coal donors could pose some risk but would be worth it, said Rep. Pramila Jayapal (D-Wash.), the other Progressive Caucus co-chair.

“The harm that’s done in taking legislative authority away from the committees is far too great,” she said. “Everyone is ready. There are a lot of champions in the rooms that we need them to be in who will be controlling the agenda.”

She pointed to anti-corruption legislation she introduced last month as a possible tool to keep lawmakers from sabotaging eventual Green New Deal legislation at the behest of powerful donors.

“Activists across the country will keep up the pressure to make sure every member is responding with the urgency that’s necessary,” she said.

The unusually speedy sausagemaking process inverts decades of Democrats’ dithering on the rapidly worsening crisis caused by greenhouse gas pollution. That mirrors the Trump administration’s aggressive efforts to unwind the few, relatively weak climate regulations that exist and to upend fragile negotiations at the 24th Conference of the Parties in Katowice, Poland, where diplomats this week are struggling to garner support for basic resolutions recognizing the scientific consensus on global warming.

The summit follows an October report from the United Nations’ Intergovernmental Panel on Climate Change that found that world governments must halve emissions over the next 12 years to avert warming of 2.3 degrees Fahrenheit above preindustrial levels, beyond which climate change is forecast to be cataclysmic. The Trump administration announced plans to withdraw the U.S. from the Paris Climate Accord, but that won’t legally go into effect until 2020. In the meantime, the administration has worked hard to further undercut the talks. The United States teamed up with Russia, Saudi Arabia and Kuwait to weaken a resolution to endorse the report — something the State Department outright refused to do.

The Democratic Party needs an answer for what their plan is to match ... the IPCC report on climate. Young people and Alexandria Ocasio-Cortez are providing a solution to that dilemma. Waleed Shahid, communications director for Justice Democrats

Yet a congressionally mandated federal report last month, using research from 13 agencies, reached similar conclusions and found that the United States is already suffering the effects of sea level rise and extreme weather.

“The Democratic Party needs an answer for what their plan is to match the U.N.’s recommendations in the IPCC report on climate,” said Waleed Shahid, the communications director for Justice Democrats, a left-wing group that played a leading role in Ocasio-Cortez’s winning primary campaign. “Young people and Alexandria Ocasio-Cortez are providing a solution to that dilemma.”

That’s not the only issue for which the Green New Deal would provide a fix. The Democratic Party has long been dogged by tensions between environmentalists clamoring for action on climate change and labor leaders warning against policies that ostracize the fossil fuel industry, which provides high-paid construction jobs. In August the Democratic National Committee, under pressure from unions, backtracked on a two-month-old resolution to ban donations from oil, gas and coal companies.

But on Wednesday, the Service Employees International Union’s Local 32BJ ― the largest property services union in the country, with 175,000 members ― announced its support for the Green New Deal resolution. Vowing to push labor leaders to give their support, Hector Figueroa, the union’s president, said, “I fully expect other unions to say, ‘We are behind this’” by early next year.

“It’s important to have a labor voice,” he said by phone. “We feel there is no future for the labor movement in this country if we don’t figure out how labor embraces more openly and more deliberately the fight to adapt and mitigate the impact of climate change.”