WASHINGTON — Most Americans are at least somewhat confident that the world will step up in its fight against global warming — but there are limits to their optimism.

That’s according to a new poll by The Associated Press-NORC Center for Public Affairs Research that also shows most think their own actions can make a difference.

About 7 in 10 Americans think it is at least moderately likely the world will take action in the next decade to reduce emissions of heat-trapping carbon dioxide and other gases, but only about 3 in 10 think that’s very likely to happen, according to the August poll.

Two-thirds of those polled said they think pollution reduction would have at least some impact in preventing future warming, but only about a quarter think it would do a lot to keep climate change at bay. About 3 in 10 Americans overall think even if emissions are cut back significantly it will do little or nothing to stop climate change.

“I worry for my children and my grandchildren and for the future and what they have in store for them,” said Vickie Jackson, of Aydlett, North Carolina. “I don’t think it’s going to get any better, unfortunately. It would take everybody to really pitch in and really care.”

Michael Mann, a prominent Pennsylvania State University climate scientist who has been labeled an alarmist by people who reject mainstream climate science, sees it a bit differently.

“I’m cautiously optimistic that we WILL take the actions necessary to avert catastrophic warming,” Mann said in an email. “However, these poll results also show that one of the greatest threats to action now isn’t outright denial. … It’s hopelessness and despair and a growing sense in some communities that we have no agency in addressing this challenge.”

Democrats and younger people show a bit more optimism than Republicans and older Americans.