Americans’ belief in the reality of global warming has increased by 13 percentage points over the past two and a half years, from 57 percent in January 2010 to 70 percent in September 2012. At the same time, the number of Americans who say global warming is not happening has declined nearly by half, from 20 percent in January 2010 to only 12 percent today.
For the first time since 2008, more than half of Americans (54%) believe global warming is caused mostly by human activities, an increase of 8 points since March 2012. Americans who say it is caused mostly by natural changes in the environment have declined to 30 percent (from 37% in March).
A growing number of Americans believe global warming is already harming people both at home and abroad. Four in ten say people around the world are being harmed right now by climate change (40%, up 8 percentage points since March 2012), while 36 percent say global warming is currently harming people in the United States (up six points since March).
In addition, they increasingly perceive global warming as a threat to themselves (42%, up 13 points since March 2012), their families (46%, up 13 points), and/or people in their communities (48%, up 14 points). Americans also perceive global warming as a growing threat to people in the United States (57%, up 11 points since March 2012), in other modern industrialized countries (57%, up 8 points since March), and in developing countries (64%, up 12 points since March).
Today over half of Americans (58%) say they are “somewhat” or “very worried” – now at its highest level since November 2008.
For the first time since 2008, Americans are more likely to believe most scientists agree that global warming is happening than believe there is widespread disagreement on the subject (44% versus 36%, respectively). This is an increase of 9 percentage points since March 2012.