A couple of months ago, before the Deepwater Horizon oil rig exploded and began spewing tens of millions of gallons of raw crude into the Gulf of Mexico, Dave Rauschkolb was just some guy with an improbable-some might even call it loopy-dream. A surfer and the owner of three restaurants in Seaside, Florida, Rauschkolb had almost single-handedly organized 10,000 people to gather on 90 Florida beaches and join hands one Saturday in February to protest an offshore-oil-drilling bill that was making its way through the State Legislature. He’d called the event “Hands Across the Sand.” In April, after President Obama announced that he would open up vast new expanses of America’s seawaters to offshore drilling, Rauschkolb heard from a woman in Virginia and a man in New Jersey who wanted to hold similar events on their beaches. He offered to help. Then the BP oil spill happened, and Rauschkolb had an idea. What if he took “Hands Across the Sand” national? He envisioned throngs of Americans joining hands on beaches all over the United States and, before long, he wasn’t the only one dreaming big.

When the Deepwater Horizon disaster occurred on April 20, the American environmental movement was already suffering perhaps the lowest morale of its 40-year existence. What had become environmentalists’ primary mission-to convince the world to do something about climate change-was, after a few hopeful years, rapidly slipping away from them. Climate activists were being outmaneuvered by the highly superior political-media operation of their fossil-fuel-industry-funded opponents. The chances of enacting any meaningful climate legislation in the United States-an essential precursor to getting the rest of the world to act-were dropping precipitously. And now, from 50 miles off the Louisiana coast and nearly a mile under the Gulf of Mexico, came this terrible, visceral image of self-inflicted environmental destruction caused by our addiction to oil. “Those of us who have worked on global warming for decades just can’t believe that here we are in a society that really has made almost no change based on the warnings that have come out,” John Passacantando, the former executive director of Greenpeace USA, says. “The deep feelings of hurt and failure triggered by the spill are just overwhelming.”

And yet any environmental activist who has been in the game long enough knows the power of a good catastrophe.