HERE under the harsh blue lights, in a cavernous ballroom of the Walter E. Washington Convention Center in Washington, D.C., people are celebrating the clean-energy revolution with their hips. It’s April 16, 2011, the second night of Power Shift, a biennial climate conference best described as a sort of TED summit for young climate activists. Whether you’re a Greenpeace organizer or a recruiter for an environmental master’s program, Power Shift is the place to trade ideas and phone numbers. Many of the attendees are undergrads, few are older than 30, and all are shaking it to a soundtrack of electro-pop and Ryan Adams. A lot of them wear their beliefs on their chests. One T-shirt reads iMATTER. Some are more colloquial: FUCK COAL, FUCK STRIP MINING.

Stage lights cue the next speaker. He’s big—35 pounds heavier than the first time I saw him talk, about a year ago—and he wears an odd piece of flair: a small orange scarf. His shaved head gleams under the lights. The crowd erupts; he smiles and speaks softly.

“Thank you for that very nice welcome,” he says. “I wish I could give you an equally nice speech. I wish I could say something really nice today that would make everyone feel really good. But sometimes the truth isn’t very nice, and it needs to be said anyway. … The truth that our movement has not been willing to talk about is that it’s probably too late for any amount of emissions reductions to prevent the collapse of our industrial civilization.”

Silence. The revolution has been paused.

Tim DeChristopher, 30, is one of Power Shift’s keynote speakers, following the author Bill McKibben; Lisa Jackson, the head of the Environmental Protection Agency; Van Jones, President Obama’s deposed green-jobs guru, now a senior fellow at the Center for American Progress; Josh Fox, the director of the Emmy-winning documentary Gasland, an investigation into the impacts of natural-gas drilling; and Al Gore. DeChristopher has not written any bestselling books, he doesn’t have a Nobel Prize, and he sure doesn’t have a government job. What he has is a B.S. in economics from the University of Utah, a nice garden in Salt Lake City, and a freshly minted criminal record.

In December 2008, DeChristopher shot to fame as Bidder 70 when he entered a Bureau of Land Management (BLM) oil- and gas-lease auction in Utah, posed as a buyer, and laid claim to 22,500 acres of wilderness worth nearly $1.8 million. His comeuppance, handed down in early March, a month before Power Shift, was a federal conviction on two felony counts: making false statements and violating the Federal Onshore Oil and Gas Leasing Reform Act. Together they carry a maximum sentence of $750,000 in fines and up to ten years in prison—a prospect that explains why he’s been packing on the muscle.

DeChristopher’s reward, however, has been a rapid rise to folk-hero status. I’ve spent the past two days wandering the convention center trying to speak with him, which can be tricky since he’s surrounded at all times by an entourage of about 15 people, members of Peaceful Uprising, the Salt Lake City–based activist group he founded. Just now they’re clustered in the front of the ballroom, watching his speech, all sporting identical orange sashes on their wrists and necks, articles of solidarity they started wearing at his trial.

After chastising the crowd, DeChristopher switches gears. His message is simple: he wants to end mountaintop-removal coal mining in his native West Virginia. “With just these people right here,” he says into the microphone, “we could send 30 people onto a mountaintop-removal site, shut it down temporarily, cost them a lot of money, start to clog up the court systems of West Virginia. And we could send 30 people the day after that, the day after that, and the day after that”—here the crowd rumbles—“every day for a year.”