Six months ago on Tuesday, climate activists with the Sunrise Movement, joined by the incoming congresswoman Alexandria Ocasio-Cortez, held a sit-in at the office of the incoming House Speaker, Nancy Pelosi, demanding that House Democrats establish a committee to draft a Green New Deal. In surveying all that has happened since, one could easily overlook the fact that the committee was never established. Democrats opted, instead, to resurrect a committee to study climate change, which has met exactly three times since January. Nevertheless, the demonstration will almost certainly be remembered as a turning point in American climate politics: Sunrise and Ocasio-Cortez have helped to push climate change to the center of American politics, with a Presidential-campaign season under way. A CNN poll in late April found that climate change was the very top issue of concern among registered Democrats and Democratic-leaning independents, with eighty-two per cent rating it as a “very important” priority for Democratic candidates to take up. That figure can be attributed, in part, to the work Sunrise’s activists have done.

Over the past month, the Sunrise Movement has held two hundred town-hall meetings, across the country, to promote the Green New Deal, a tour that ended on Monday night, in a packed auditorium at Howard University, in Washington, D.C. About fifteen hundred mostly young students and activists turned up to hear from the Sunrise Movement’s leaders and allies, including Ocasio-Cortez and Bernie Sanders, in an event that approached, at times, the fervor of an evangelical revival. Sunrise’s charismatic twentysomething co-founder Varshini Prakash explained her commitment to climate activism in the urgent, personal language that has come to define the group. “I currently live in a place called East Boston, and that’s a place where, if we don’t take action in the next couple of decades, will cease to exist and will be lost to the seas forever,” she said. “I’m also the child of two South Indian immigrants, and India is a place that has been completely devastated by the climate crisis. Just last fall, I watched as over one million people were displaced and put in refugee camps in their own state, where my family’s ancestral homelands are, because of climate-fuelled monsoon seasons. And I’m here because I believe that no person should ever have to live in fear of losing the people that they love or the places that they call home due to crises that are preventable.” Later, Prakash led the room in a gospel-inspired song. “We gonna rise up / Rise up ’til it’s won / When the people rise up / The powers come down.”

The Sunrise Movement owes much of its influence in Democratic politics to its earnestness; its members are as difficult to dismiss, as Dianne Feinstein learned after a confrontation with young activists in February, as they are to ignore. Even longtime environmentalists who are supportive of Sunrise and the Green New Deal have found themselves at odds with the scale of the group’s ambitions and the new mood of the young left concerning climate change. One of last night’s guests was the Green New Deal resolution’s lead Senate sponsor, Ed Markey, who addressed right-wing criticisms of the proposal during his speech.“The critics have lined up to take their shots at the Green New Deal,” he said. “Totally bogus stories about ice cream and hamburgers and airplanes. They call the Green New Deal pie in the sky. They call it socialism!” At this, the crowd broke out in cheers, and Markey, who evidently did not expect that, shook his head.

As if on cue, Sanders followed Markey, giving a climate-focussed and enthusiastically received version of his standard stump speech, with one refreshingly impromptu moment, during his riff explaining opposition to climate action. “The truth is that, right now, we have a small number of incredibly powerful billionaires who exercise enormous influence over the economic and political life of our country,” he said. “That is exactly what is going on with the fossil-fuel industry. Like the tobacco industry of fifty years ago—you all remember that?”

A few people in the audience said, “Yeah.”

“Well, I know you weren’t born yet, but you read about it,” he said, to laughs. “I do remember it,” he said, chuckling. “You had an industry who denied, under oath in Congress, that cigarette smoking causes cancer and other diseases, and the fossil-fuel industry is doing exactly the same right now.”

Sanders consistently trails the frontrunner among the Democratic Presidential candidates, Joe Biden, in polls of Democratic primary voters, a situation that has some pundits questioning the wisdom of the field’s swing to the left. This week, one of Biden’s advisers told Reuters that he is pursuing a “middle ground” on climate policy. Progressive activists, of course, would like to see the leftward drift continue. During a panel on Monday Night, Alexandra Rojas, the executive director of the group Justice Democrats, emphasized the need to primary Democrats who are soft on climate. And, during her speech, Alexandria Ocasio-Cortez criticized “both sides” of the aisle for sidelining climate action, including moderates who, in her words, have said that the Green New Deal aims to achieve “too much.”

“What’s ‘too much’ for me is the fact that, in 1989, the year that I was born—the year that many of us were born, and in years after and right before—that politicians were first informed by NASA, that Congress was first notified by NASA that climate change was going to threaten my life and everyone here’s life to come, and they did nothing,” she said. “That is too much for me. And I will be damned if the same politicians who refused to act then try to come back today and say we need a middle-of-the-road approach to save our lives!”

Yet, despite their confrontational rhetoric, Sunrise and their allies seem to have entered into something like a détente with the Democratic establishment. In March, Sunrise opted to support the Senate Democrats’ strategy of voting present on Mitch McConnell’s Green New Deal vote rather than insisting that the caucus take a clear stand on the proposal. At the end of Monday night’s event, Prakash announced that Sunrise would demand that all Democratic candidates refuse fossil-fuel-related donations, support holding a climate-focussed debate during the primary, and make the Green New Deal a priority on their first day in office, should they be elected—a very low set of bars for the many candidates who have already voiced nominal support for the Green New Deal.

When Beto O’Rourke released his climate plan, last month, Sunrise issued a statement saying that O’Rourke had got “the science wrong” and that he was out of step with “the scale of action that scientists say is necessary to take here in the United States to give our generation a livable future.” But, during a panel on Monday night, Rhiana Gunn-Wright, of the new progressive think tank New Consensus, one of the policy minds behind the Green New Deal, seemed to offer more flexibility. “The next decade is crucial—it is crucial for us being able to have a healthy climate, and 2050, whatever time line people choose, more time is not an excuse to maintain the status quo for as long as possible,” she said. “Whether you decide it’s 2030, 2040, 2050—from here on out, to move off of the energy source that we have used for over a hundred years, it is going to be a sprint from now until the end.”

It’s unclear whether being more accommodating to plans like O’Rourke’s will pay political dividends in the end. But it is clear, as the group has insisted so effectively, that the time to begin seriously addressing climate change is running out. As Ocasio-Cortez noted in her speech, climatologists announced this week that the atmosphere had just reached a CO 2 concentration of four hundred and fifteen parts per million, a level of atmospheric CO 2 last matched three million years ago, before humans walked the Earth.

“I wish that, as a leader, I could give you comfort about the future,” Ocasio-Cortez told the crowd. “I wish that, as a public servant, I could come here and tell you that everything’s going to be all right. But I can’t tell you that today, because I’m not interested in lying to you. Frankly, there is no reason for us to be comfortable right now. We are at four-fifteen. Four-fifteen. There is no reason for us to be comfortable, and I’m not here to guarantee to you that everything will be O.K. But what I am here to say is that we must try.”