What will it take to convince sceptics of global warming that the phenomenon is real? Surely, many scientists believe, enough droughts, floods and heat waves will begin to change minds.
But a new study led by a Michigan State University scholar throws cold water on that theory.
Only 35 per cent of US citizens believe global warming was the main cause of the abnormally high temperatures during the winter of 2012, Aaron M. McCright and colleagues report in a paper published online today in the journal Nature Climate Change.
''Many people already had their minds made up about global warming and this extreme weather was not going to change that,'' said McCright, associate professor in MSU's Lyman Briggs College and Department of Sociology.
Winter 2012 was the fourth warmest winter in the United States dating back to at least 1895, according to the National Oceanic and Atmospheric Administration. Some 80 per cent of US citizens reported winter temperatures in their local area were warmer than usual.
The researchers analysed March 2012 Gallup Poll data of more than 1,000 people and examined how individuals' responses related to actual temperatures in their home states. Perceptions of warmer winter temperatures seemed to track with observed temperatures.
''Those results are promising because we do hope that people accurately perceive the reality that's around them so they can adapt accordingly to the weather,'' McCright said.
But when it came to attributing the abnormally warm weather to global warming, respondents largely held fast to their existing beliefs and were not influenced by actual temperatures.
As this study and McCright's past research shows, political party identification plays a significant role in determining global warming beliefs. People who identify as Republican tend to doubt the existence of global warming, while Democrats generally believe in it.
The abnormally warm winter was just one in an ongoing series of severe weather events – including the 2010 Russian heat wave, Hurricane Sandy in 2012 and the 2013 typhoon in the Philippines – that many believed would help start convincing global warming cynics.
''There's been a lot of talk among climate scientists, politicians and journalists that warmer winters like this would change people's minds,'' McCright said. ''That the more people are exposed to climate change, the more they'll be convinced. This study suggests this is not the case.''
McCright's co-authors are Riley E. Dunlap of Oklahoma State University and Chenyang Xiao of American University.