Recent polling conducted by the Pew Research Center suggests that a greater number of people in the U.S. are accepting the reality of climate change. 67 percent of Americans said that there is "solid evidence" that average global temperatures have been rising in recent decades, signaling a gain of four points since last year and 10 points since 2009. Yet only 42 percent say this warming is "mostly caused by human activity," according to Pew.
In a presidential election marked by accusations of "climate silence" and a lack of forthright discussion of what has been called a "planetary emergency," the Pew polling reveals another stark difference between supporters of Barack Obama and Mitt Romney.
Only 42 percent of Romney supporters say there is strong evidence of global warming and a paltry 18 percent acknowledge its human origin. This 42 percent stands in sharp contrast to the 88 percent of Obama supporters who say that average global temperatures are on the rise and 63 percent who say it is anthropogenic. Among Republicans overall, 48 percent say there is "solid evidence" of global warming, up from 35 percent in 2009.
Despite these numbers, at least 97 percent of the most actively publishing climate scientists and nearly a dozen of the world's most prominent national science academies acknowledge that the world's climate is changing as a result of increasing atmospheric concentrations of greenhouse gases, mostly from the burning of fossil fuels. According to the Pew poll, 45 percent of Americans -- including 58 percent of Democrats and 30 percent of Republicans -- answered yes to the question "Do scientists agree earth is getting warmer because of human activity?"
NASA scientist James Hansen recently said, "There's a huge gap between what is understood by the scientific community and what is known by the public."
Amid a year of record temperatures and severe drought, Hansen and his colleagues released a statistical analysis suggesting that the odds are too great for many of the past decade's most extreme weather events to have happened by chance. He wrote in the Washington Post, "our analysis shows that, for the extreme hot weather of the recent past, there is virtually no explanation other than climate change."
The increase in greenhouse gases has also warmed the world's oceans, posing threats to marine life and the food security of island nations. The lead author of a 2012 study on warming oceans, Lawrence Livermore National Laboratory climate scientist Peter Gleckler, said, "most of the observed global ocean warming over the past 50 years is attributable to human activities."
According to Pew, these numbers are based on telephone interviews in the first week of October of just over 1,500 American adults in all 50 states and the District of Columbia.