“It’s a powerful experience, getting arrested,’’ [Sam Novey, 23] said. “It was a hard choice for me, as a young person. Who knows what it will mean for me down the road? But there were these gray-haired ladies from Alberta, where the pipeline starts. There were religious leaders from all the traditions in their collars and yarmulkes, and it got me thinking the way that science and morality are connected.

> “Twenty years ago, we could say we didn’t know. Now the science is clear. Once we know, to not act is a moral choice.’’