The results are based on Gallup’s annual Environment poll, conducted March 6-9. Only about half of those who expect global warming to occur during their lifetimes, 51%, believe it will pose a serious threat to their way of life. This explains the gap between Americans’ perceptions that global warming is occurring and that it will be a threat.

Although the gap between the perceived occurrence and perceived threat of global warming remains wide, it is narrower than in the past. The percentage of Americans who believe global warming’s effects will happen during their lifetimes is the same now as it was in 1997, when Gallup first asked the question, and is among the lower readings over that 17-year span. During that same period, the percentage who believe global warming will threaten their way of life has increased from 25% to 36%.

Gallup’s 2008 survey marked the peak in the belief that global warming will happen during one’s lifetime (75%) and that it will seriously threaten one’s way of life (40%).