On June 23, 1988, record 38°C temperatures in Washington DC provided a persuasive backdrop for NASA’s Jim Hansen to force the greenhouse effect into our consciousness. At least one of the senators hearing his landmark congressional testimony was well aware that the heat would help sear the message into people’s minds. Tim Wirth has since admitted turning off the air conditioning and opening the windows the night before, so Jim’s sweat would be obvious for the TV cameras.
That baking hearing likely played on how we think in a way psychologists had just started to untangle in the previous decade. That is, how we judge things is often dominated by a simple sense of our personal experience, rather than a deeper analysis of evidence available to us. “Numerical judgments are hard, so we grasp at whatever more tangible we can find,” Elke Weber, from Columbia University in New York, explained.
Identifying this tendency to answer an easier question, known as substitution, helped psychologist Daniel Kahneman win a Nobel Prize for Economics. And when it comes to our opinion on climate change, recent temperatures are especially important, Elke and her colleagues have shown over the last three years.
In 2010, a rather different extreme in the US capital drew Elke’s husband Eric Johnson to study this effect. Then, two massive snowstorms struck in one week in February, an event that was dubbed the ‘Snowpocalypse’, leading senators to deride the possibility of climate change. His team therefore looked at whether local weather information gets falsely substituted for global climate in three studies in the US and Australia.
Across three studies they asked people their opinions on global warming and whether the temperature on the day of the study was warmer or cooler than normal. Those who thought that day was warmer than usual believed more in and had greater concern about global warming than people who thought that day was colder than usual. They would also donate more money to a global-warming charity if they thought that day seemed warmer than usual. Read the rest of this entry »