The Sunrise Movement, a group of young environmental activists that organize throughout the United States, caused a stir last week when more than 150 of its members staged a sit-in at House Minority Leader Nancy Pelosi’s office in Washington, D.C., to demand aggressive action against climate change. Ultimately, 51 young people were arrested.

The movement’s main goals are to convince legislators to stop taking money from the fossil-fuel industry and to pledge their support for a Green New Deal, a plan which charts a path to a 100 percent renewable energy economy in the 12 years before the effects of climate change become irreversible. Right now, the young activists — who range in age from 12 to 25 — are targeting Democratic representatives and representatives-elect in preparation for their retaking of the House.

On its face, the Sunrise Movement is divisive; its tactics embolden Democrats’ younger, progressive wing while irritating the old guard who believe the party should unite against Republicans. But regardless of the intra-party fight, these kids aren’t going away. Alexandria Ocasio-Cortez, the immensely popular Democratic socialist and youngest woman ever elected to Congress, even joined their protest in front of Pelosi’s office last week.

The movement is also already having a tangible effect. Later in the day of the sit-in at Pelosi’s office, Ocasio-Cortez unveiled her proposal for a select committee for a Green New Deal. Since then, 11 House Democrats have joined Ocasio-Cortez to pledge their support. The stunt made such waves that Pelosi had to release a statement urging police to release the demonstrators.

“I believe we are in a fight for the soul of the Democratic party right now,” Claire Tacherra-Morrison, a 24-year-old activist with the group, told VICE News.

Later that week, Sunrise activists also stormed the office of Democratic Rep. Frank Pallone, the incoming chair of the House Energy and Commerce Committee, to demand that he support Ocasio-Cortez’s committee. Pallone said he supported the protesters’ mission but stopped short of supporting Ocasio-Cortez’s committee.

"I believe we are in a fight for the soul of the Democratic party right now."

Climate policy experts say the Green New Deal is an achievable goal, but Sunrise faces a steep uphill political battle. Republicans still control the White House and the Senate, and most of the Democrats who have signed on to support the deal are hard-left progressives. Passing any hard policies this term might be a pipe dream, but if the movement can stir-up enough of an impression, the odds could be in its favor come 2020.

“Any plan that isn't this time-sensitive and justice-oriented, isn't responding to the crisis at hand,” Jesse Meisenhelter, Sunrise’s spokeswoman, told VICE News.

At 24, Meisenhelter is older than many people working with the Sunrise Movement, which is largely made-up of students who apply for 6-month, $4,800 fellowships funded by grassroots donors. Sunrise raised $1 million in donations in its first operating year, which began in May of 2017. As part of the program, the young activists are placed in “critical states” like Michigan, Florida, and Pennsylvania to organize on the ground.

VICE News spoke with several activists — many of whom were arrested at the Pelosi sit-in — and their reasoning for joining the movement is usually personal.

“I was living in the Bay area, and I remember one night I woke up in the middle of the night and I smelled smoke. I was worried it was in the city,” said Tacherra-Morrison, a recent graduate of UC Berkeley, of blazes in California that have killed at least 81 people and have left about 700 missing. “Then I looked into where the fire actually was. It was in my hometown, which is up north. My parents were evacuating.”

“These fires are raging across the state, and it’s not getting better,” she added. “People are walking with masks on their faces. For me, we can’t afford to not be taking that action because it’s our loved ones at stake.”

On Tuesday, activists representing the Sunrise Movement once again staged actions across the United States — about 300, to be specific, according to a spokeswoman for the initiative. Tuesday’s youngest activist, 12-year-old Haven Coleman, led an action at Democratic Rep. Diana DeGette’s office in Colorado. These actions range from large protests such as sit-ins or something as small as visiting a representative’s office to discuss the Green New Deal with staff.

Philip Brown, a 20-year-old originally from Jamaica who left Clark University in Massachusetts to join the Sunrise Movement, echoed others’ fears that the effects of climate change could hurt his loved ones, such as hurricanes that have ravaged the Caribbean islands, where he grew up.

“That could have easily been my people, that could have easily been my country,” Brown said. “To stop climate change is to stop the systems that prioritize profit over people.”

It’s a theme that Sunrise activists returned to time and again: that capitalism and greed in the fossil-fuel industry are responsible for the crisis facing future generations.

“When I graduated from high school, I knew our time was running out,” said Jeremy Ornstein, an 18-year-old who opted to join the Sunrise Movement instead of going to college. “Our bodies are on the line. It’s our safety that’s being threatened. It’s being threatened in big ways because failed leadership is being bought out by corporations.”

Ornstein, who appeared in a viral video giving a speech at a protest last week, said students who survived the shooting in Parkland and ignited a new gun-control movement were a major inspiration of his. And the Sunrise activists are organizing in similar ways: In March of next year, many climate activists will go on a tour to recruit other young people to join their movement.

Climate change is an issue that’s vitally important to young people, perhaps even more than gun control. Dana R. Fisher, a professor of sociology at University of Maryland and author an upcoming book The American Resistance, has studied large-scale organized protests since the Women’s March. She said that, according to her data, the environment is the most important issue for “resistance” activists. About 17 percent of respondents in her near three-year study said the environment was the most important issue facing the nation today, followed by the 15 percent who said civil rights. Guns, at 6 percent, came in at fifth.

Top Democrats have pointed to infrastructure as one their top priorities as they retake the House. The problem is that infrastructure isn’t a very “sexy” topic when you’re up against President Donald Trump, Fisher said. It didn’t even make the top 15 most important issues in the protesters she surveyed. But the Green New Deal — which includes plans for building a “smart” grid and “decarbonizing, repairing and improving transportation and other infrastructure” —l takes an issue that young people are passionate about and ties it to infrastructure.

“They did seem to get some attention from Pelosi,” she said. “Democracy has been reinvigorated in all these ways, and young people are paying a lot more attention to institutional politics.”