Twenty-five percent of the 1,000 adults surveyed in July said they think global warming is the biggest environmental challenge the world faces. That figure is lower than the 33 percent who responded in a similar poll conducted last year; but higher than the 16 percent who responded in 2006.
ABC News pollster Gary Langer says the decline in environmental concern is partly due to the shift of media attention to the presidential election and the sluggish U.S. economy.
Pew Research released similar findings in May, reporting that the proportion of Americans who say that the earth is getting warmer has decreased since January 2007.
A Harris Poll released in June, also revealed that most Americans are making lifestyle changes to help the environment.