This year, the meeting will focus on a more nuanced question: “Global warming: Was it ever a crisis?”

Most of the talks at the meeting will challenge climate orthodoxy. But some presenters, including prominent figures who have been vocal in their criticism in the past, say they will also call on their colleagues to synchronize the arguments they are using against plans to curb greenhouse gases.

In a keynote talk Sunday night, Richard S. Lindzen, a professor at M.I.T. and a longtime skeptic of the mainstream consensus that global warming poses a danger, first delivered a biting attack on what he called the “climate alarm movement.”