In a Pew poll in early September 2005, shortly after Hurricane Katrina, just a quarter of Americans thought climate change likely was responsible for its severity. Two-thirds said it was more likely “just the kind of severe weather that happens from time to time.”

As the storm’s impact became clear, more, 39 percent, blamed climate change just weeks later, and this moved to a near-even 45-49 percent by 2006. It’s flipped entirely in the ensuing decade: In this poll, produced for ABC by Langer Research Associates, 55 percent mainly blame climate change, vs. 41 percent happenstance.