Naomi Klein, an author on environmental and economic issues, has sharply criticized what she called “a very deep denialism in the environmental movement among the big green groups,” like the Environmental Defense Fund, which has worked with fossil-fuel companies to research methane leaks and to pursue market-based solutions to the climate crisis, like putting a price on carbon.

Ms. Klein argues that capitalism inherently worsens climate change. Working within the system as the institutional players do, she has said, is “more damaging than the right-wing denialism in terms of how much ground we’ve lost.”

Mr. McKibben said the kind of noisy activism that characterizes the work of organizations like 350.org helps correct what he sees as the institutional inertia of the established groups. He said the lack of mass-movement activism was a key reason behind the failure of legislation like the 2010 effort to develop a system to limit and put a price on greenhouse gas emissions.

“If we’re going to win the climate fight, it will come with a change in the zeitgeist,” he said. “And that — not particular pieces of legislation — is the ultimate point of building movements.”

Fred Krupp, the president of the Environmental Defense Fund, disagreed. Working with industry, he said, had helped deepen the understanding of such issues as methane leakage, which could produce remedies.

“More and more businesses want to be part of the solution,” Mr. Krupp said. Collaborative efforts helped lead to last month’s bipartisan passage of an overhaul of toxic substances legislation, he said, adding, “And we’re getting close to being able to do it with climate change.”

Given these fault lines on various issues, a question naturally arises: Are they hurting the overall environmental movement?