By Matt Kaplan

The use of dire predictions to encourage action on climate change may be backfiring and increasing doubt that greenhouse gases from human activities are causing global warming.

Although scientific evidence that anthropogenic activities are behind global warming continues to mount, belief in the phenomenon has stagnated in recent years. "When I was a pollster, I was detecting that many dire messages seemed to be counterproductive, we really needed someone to determine why," says Ted Nordhaus at the Breakthrough Institute, a Californian think-tank for energy and climate issues.

Matthew Feinberg at the University of California, Berkeley, wondered whether presenting children as the main victims of climate change, a common feature of warning messages, might be viewed as unfair because children have not caused global warming. He speculated that this, along with the apocalyptic descriptions of global warming's possible consequences, might threaten people's natural tendency to believe that the world is a fundamentally fair and stable place. Undermining that belief has been shown to increase the likelihood that people will ignore reality and allow events to unfold around them without intervening.

Hard-hitting

A few psychologists have explored the psychology of climate-change belief, with some work revealing that climate skepticism relates to peoples' tendency to defend the status quo, but little else has been done. "We saw a giant hole in the literature when it came to looking at psychological responses to global-warming messages," says Feinberg.

So Feinberg and his colleague Robb Willer, also at Berkeley, asked 45 online participants spread across 15 cities in the United States to engage in what was ostensibly a sentence-unscrambling activity.

Half of the volunteers were asked to unscramble sentences such as "Somehow justice will always prevail", whereas the others were given sentences such as "Often, justice will not prevail". This activity primed them to have either a strong or weak belief in a just world. The participants then completed a survey that measured their scepticism over climate change, asking questions such as "How solid is the evidence that the earth is warming?" and requiring participants to rate their answers on a six-point scale, in which six was not at all solid and one very solid.

Next, participants watched two short global-warming warning videos created by the Environmental Defense Fund, a charity based in New York that campaigns on green issues. The first showed a train speeding towards a small girl as a metaphor for the impending catastrophe that awaits the world's children (see video). The second showed anxious children verbally simulating a clock ticking while describing the climate devastation that is coming (see video). After watching, participants again had their degree of skepticism over climate change measured. They were also asked to rate how willing they were to take action to reduce their carbon footprints.

Off-target?

Feinberg and Willer found that participants primed to have a stronger belief in a just world reported levels of skepticism that were 29 percent higher, and a willingness to reduce their carbon footprint that was 21 percent lower, than those primed to see the world as an unjust place. Their findings are reported in Psychological Science.

"The idea that persuasion is most effective when it matches a person's belief systems is something we have known about for a while, but what is nice about this research is that it identifies the just-world belief system as a key matter for climate-change communicators to attend to," says psychologist Janet Swim at Pennsylvania State University in University Park.

However, whether the findings will change the way in which global-warming threats are communicated is not clear. "While the authors are certainly raising valid points, strong messages do have a place in activating people who are already with you," explains Keith Gaby, communications director of the climate section at the Environmental Defense Fund.

Gaby argues that the fund's videos do effectively target the people that they are trying to reach. "One of our current ads has a child in it and is hitting the same emotional buttons that the train video does, but we are trying to send a message to Congress with it rather than communicate with the public," he says. "If we were running a $50-million ad campaign to change the minds of skeptics that would be different, and we would certainly consider these findings."