The 66% of Democrats worrying a great deal about the issue is the highest percentage in Gallup’s annual polling on the question since at least 2000 and is nine percentage points above last year’s previous high of 57%. Forty-five percent of independents now say they worry a great deal, a jump of 11 points from 2016. The rise in concern among both Democrats and independents has pushed the overall percentage of Americans saying they worry about global warming to 45% — the highest level in nearly three decades of Gallup polling. Republicans’ 18% who say they worry a great deal is the same as last year’s percentage and 11 points below the party’s high of 29% in 2000.

The widening gap between Republicans and Democrats comes after a year that highlighted vast differences between the parties on global warming issues. In April 2016, the United States joined 195 other countries in signing the Paris Agreement on climate change — the most comprehensive international agreement to date on combatting global warming. It had been a long-standing goal of Democratic President Barack Obama, who said of the day the agreement was signed: “History may well judge it as a turning point for our planet.”