Global Warming Concern at Three-Decade High March 14, 2017 · Leave a Comment Record percentages of Americans are concerned about global warming, believe it is occurring, consider it a serious threat and say it is caused by human activity. All of these perceptions are up significantly from 2015. CONT. Lydia Saad, Gallup Share:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on Reddit (Opens in new window)Click to email a link to a friend (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Tumblr (Opens in new window)Click to share on Pinterest (Opens in new window)MoreClick to print (Opens in new window)