One Monday morning last April, an Englishman named Simon Bramwell glued himself to a glass door at Shell’s London headquarters and refused to leave.

Bramwell, 47, is a co-founder of Extinction Rebellion, a two-year-old climate-activist group dedicated to the belief that real change will only come through mass civil disobedience. For the next 10 days, XR, as the group is known for short, launched a series of coordinated actions targeting several sites throughout London — blocking traffic outside the stock exchange, interrupting train service at Canary Wharf, and generally bringing the city’s business to a snarling standstill.

The atmosphere was more jovial street fair than window-smashing anarchist mob. Activists brought potted trees to the middle of Waterloo Bridge and danced to a samba band while shutting down Parliament Square. More than 1,000 people ended up being arrested — teenage students, octogenarian retirees, teachers, construction workers, doctors and nurses, and a 41-year-old marine biologist who was seven-months pregnant — many of them for the first time.

Extinction Rebellion is part of a new generation of activists treating global warming not simply as an environmental problem, but an existential one — and amplifying their tactics accordingly. Though their public demonstrations are now on hold because of the coronavirus, there is no doubt that they will be back at it as soon as the pandemic passes. With the science growing increasingly dire, and the world’s governments still refusing to act (or worse, denying there’s a problem), marches and calls to Congress, these groups say, aren’t enough. “Unfortunately, people just don’t pay attention to petitions,” says Liam Geary Baulch, 26, an action coordinator with XR. “Movements win by causing disruption.”

Or as another activist put it: “You can have a million people marching each week and no one cares. But you block a road, people take notice.”

XR has positioned itself in explicit opposition to older, more established groups like Greenpeace and the Sierra Club, whom XR views as insufficiently confrontational for the crisis at hand. One of XR’s very first actions was to occupy Greenpeace’s office in London, where protesters delivered cake and flowers to the staff while simultaneously imploring them to up their game. “Failure to do things differently, when everything is failing,” an XR statement said, “can only be described as complicity.”

Greenpeace, of course, is no slouch in the law-breaking department, with a long history of provocative actions and hard-won victories. But even some leaders acknowledge that their more targeted, small-scale approach — while effective — has been outpaced and dwarfed by the sheer enormity of the problem. “The movement has evolved because it wasn’t working,” Annie Leonard, executive director of Greenpeace USA, has said. “The science is stronger than ever, and we’re still losing.” Now, even Greenpeace is starting to take a page from XR’s civil-disobedience book, co-organizing Jane Fonda’s Fire Drill Fridays, in which the actress and her supporters get arrested the first Friday of each month.

At first blush, the concept of a “rebellion” to combat climate change might sound extreme. But given both the incomprehensible scale of the catastrophe and the inertia we must overcome, it also seems almost comically pointless to, for example, stand outside a grocery store holding a clipboard, asking people if they have a minute for the environment. If society is going to change as drastically and urgently as we need it to, some level of painful disruption seems necessary.

But how much? At one end of the spectrum, emails and petitions seem too easy to ignore. But disrupt too much — start getting people fired because they can’t make it to work on time, or prevent an ambulance from reaching a hospital — and you risk turning off the exact people whose support you need. What, then, is the proper degree of nuisance for a climate activist? How far is too far — and how far is not nearly far enough?

In some ways, this new breed of aggressive climate activists hearkens back to the earliest environmental radicals who broke the law in defense of the planet. Although groups like Earth First! and the Earth Liberation Front had much narrower goals (wildlife conservation, stopping animal testing) and much more destructive tactics (vandalism, firebombing), the challenge they faced was more or less the same. “It is not enough to write letters to congressmen, deliver sermons, make speeches, or write books,” author and activist Edward Abbey wrote way back in 1983. “The Earth that sustains us is being destroyed.… We need more heroes and heroines — about a million of them.”

“Yes … we must continue to take part in political action,” Abbey added. “But at some point we must also be prepared to put our bodies on the line.”

Extinction Rebellion was started in Stroud, a quaint, bohemian town (population 30,000) in the rolling hills of southern England. Several members had roots in the Occupy movement; others were vets of anti-fracking and air-pollution campaigns. But they all agreed that what they’d been doing wasn’t working. They devised a name for their group that would be alarming on purpose, to jar people out of complacency. For a logo, they chose the extinction symbol: an hourglass, as in, time is running out.

“I think [XR] really came out of a sense of frustration and a deep grief that so many different environmental groups had tried so many things, and it’s still getting worse,” Baulch says. “Maybe it’s time to take bigger risks.”

From the start, the group set out to adopt the so-called civil-resistance model — forcing change by peacefully breaking the law. According to its research, history’s most successful mass uprisings — from the American civil rights movement to the British suffragettes to the Arab Spring — had some key things in common. First, they were absolutely nonviolent. Second, they involved a critical mass of people gathering in a capital city, where the media and power reside. And third, they broke the law and got arrested.

“Politicians seem to be much more afraid of large numbers of people getting arrested than a small number of people doing a higher-risk thing,” says Baulch. “The idea was, how can we get people to move from being concerned, to saying, ‘I’m going to make a sacrifice. I’m going to risk legal action and sit down in the road.’ In a way, we were lowering the bar for entry by saying you don’t need special skills like driving a boat. So rather than have people saying, ‘Oh, those environmentalists over there, they’re really brave, they’re doing it for us,’ this was about ‘How do we make this everyone’s concern? How do we make it so everyone is implicated.’”

“There’s something materially different about going on a march on a Saturday morning versus going out and getting arrested,” says Clare Farrell, 37, another XR co-founder. “It’s about calling out the government — saying the social contract is broken, and this is a dereliction of your primary duty to protect your citizens.”

XR’s strategy is most fully laid out in a manifesto by co-founder Roger Hallam, called Common Sense for the 21st Century. Hallam, a 53-year-old organic-farmer-turned-academic, did his doctoral work on the history of civil disobedience and radical movements — from Gandhi and the struggle for Indian independence to the revolution in Ukraine. (He’s joked that he has a Ph.D. “in how to cause trouble effectively.”) “We have to be clear,” Hallam has written. “Conventional campaigning does not work. Sending emails, giving money, going on A-to-B marches. Many wonderful people have dedicated years of their lives to all this, but it’s time to be honest.… You cannot overcome entrenched power by persuasion and information. You can only do it by disruption.”

“We need to get arrested,” Hallam writes in his book. “Tens of thousands of us. No more protests or petitions. Instead, nonviolent disobedience, lots of it and on a large scale. Close down cities until the politicians take action.”

XR’s public debut came in October 2018, when a few dozen activists, including Greta Thunberg, gathered in front of a crowd of 2,000 at the U.K.’s Parliament and issued a “Declaration of Rebellion.” They had three demands: First, that we as a society collectively tell the truth about how fucked we are. Second, that the government commit to reducing greenhouse emissions to net-zero by 2025. And third, that Britain establish a democratic Citizens’ Assembly — free from corruption and special interests — to best decide how to deal with the threat of climate change.

Baulch was one of a dozen XR activists arrested that day. “It was really important that we showed our strategy from the beginning,” he says. But it was six months later that XR truly entered the mainstream, with its massive protests in April 2019. Tens of thousands of regular people, from elementary schoolers to nonagenarians, helped lock down locations throughout London. “To be honest, I didn’t think we’d be able to occupy any of the sites for more than a day,” Baulch says. “And somehow we managed to occupy all of them for at least a week.”

The campaign cost London more than $20 million in police overtime, plus untold millions more in lost productivity. The action won huge attention for XR and, more important, widespread public support. Within a month, Parliament had given into their first demand and declared a climate emergency.

There are three key things to note about the civil-resistance model as practiced by XR. First, it isn’t all doom and gloom. The actions are planned to be fun and inviting, so people want to participate. “We try to think about how can we disrupt these roads in the most nonviolent, loving way possible,” says Baulch. “Crowds of people planting trees, singing songs, and waving colorful flags look inviting, as opposed to a purely angry mob.” As Hallam writes, “The general atmosphere should be: ‘We’re going to take down the government and have fun doing it.’”

Second, the actions are designed to be disruptive, but not too much. For instance, XR canceled plans to shut down Heathrow airport, and it tries to work with police in advance to make sure it isn’t blocking emergency routes or risking the public’s safety. The goal is to find the sweet spot at which XR is not endangering or alienating people yet still causing enough headaches that it can’t be ignored. “The process of political change involves people getting pissed off,” Hallam once said. “So the key issue is not whether they get pissed off, it’s whether them getting pissed off leads to attitude change.”

Finally, and perhaps most important, civil resistance doesn’t require a majority in order to be successful. According to XR, there’s a tipping point at which a movement’s momentum will carry it to success. “We should not make the mistake of thinking ‘the people have to rise’ in the sense of the majority of the population,” Hallam writes. “We need a few to rise up, and the rest will be willing to ‘give it a go.’”

This strategy is based in large part on the work of Harvard professor Erica Chenoweth, the co-author of a book called Why Civil Resistance Works. Chenoweth studied more than 300 movements since the turn of the 20th century, and according to her research, the magic number for success is surprisingly small: only 3.5 percent. Which is to say, every nonviolent movement she looked at that had the active participation of just 3.5 percent of the population was a success.

In other words, if just a few hundred thousand people can mobilize in New York City, it might be enough to spark massive structural change. “There’s lots of people who disagree with what we do,” says Baulch. “But you don’t need the whole population to act. You just need a majority of the population to not be against you.

“If you look at the polling that was done after our big rebellion in April,” he adds, “you saw a huge increase in the number of people in the U.K. who thought climate change was one of the top issues we need to focus on right now. And you saw the media start to cover climate change as if it’s an emergency. So even if people disagree with our tactics, they still might realize, ‘Oh, shit. I actually do want my kids to have a future.’”

Extinction Rebellion is growing worldwide, with nearly 800 branches in more than 57 countries. Here in the U.S., where there are dozens of chapters from Montana to Miami, XR members in New York shut down Times Square last October, and more than 60 people were arrested. A good start — though far from a revolution.

Stateside, the most successful new group is the Sunrise Movement — a self-described “army of young people” taking a more traditionally political route. Sunrise, which was born in 2013 inside a borrowed office at the D.C. chapter of the Sierra Club, grew out of the campus divestment movement, where students pushed their colleges and universities to stop investing in fossil fuel. It made its first big splash in November 2018, when 51 young people were arrested after taking over Nancy Pelosi’s office and calling on her to support the Green New Deal. A just-elected Rep. Alexandria Ocasio-Cortez stopped by to show her support, and the videos went viral.

Sunrise has boomed in part because it’s been savvy about communicating with Gen Z’ers and millennials: The group is fluent in Twitter-speak, handy with memes, and knows how to engineer a viral moment, like a subsequent sit-in at Sen. Dianne Feinstein’s office where the 85-year-old California moderate lectured the kids on political realism but mostly succeeded in winning more converts to Sunrise’s cause.

So far, the movement has devoted most of its energy to organizing politically: pressuring lawmakers, advocating for legislation, and helping get out the vote. In January, Sunrise endorsed Bernie Sanders, and its top priority this year is mobilizing young voters in November. But according to the group’s five-year plan, while 2020 is about winning the election, 2021 will be dedicated to “engag[ing] in mass noncooperation to interrupt business as usual.”

As of a few weeks ago, Extinction Rebellion was gearing up for another worldwide campaign, starting May 23rd — one that it hoped would be even bigger. “We’re calling it a rolling rebellion,” said Clare Farrell at the time. “The goal is sustaining it for six weeks. We’ve done quite well at ringing the alarm. Now we’re focused on mobilizing as many people as possible. Our ambition is to get a million people activated this year.”

Obviously, the coronavirus hit pause on all that. Extinction Rebellion NYC recently announced they were postponing their major spring protests until at least the summer, and for the foreseeable future, XR actions everywhere — like so much of life these days — are migrating online. In late March, Extinction Rebellion UK issued a new set of suggestions for how to mobilize during the pandemic, including growing the movement digitally and planning actions for a drastically changed world. “There will come a time,” a statement read, “for us to be out on the streets together again.”