Three in five Americans say that extreme weather is related to climate change. Most expect climate change to have a “significant negative effect” on the world in their lifetimes. 60% of Americans say that extreme weather events in the United States over the last few years are related to climate change. 67% of Americans say they're concerned about climate change, including 42% who are "very" concerned. 55% of Americans believe that climate change will have a significant negative effect on the world in their lifetime.