Perception of risk for climate change
Feb 06 2014
According to IPCC, although climate change is a serious problem, there are uncertainties in climate change about the future cost (how much?), timing (when?), and probability (with what chance?) of occurrence of consequences. These uncertainties are somewhat driven by the lack of consensus among climate experts on the probability and timing of future climate consequences. For example, according to the IPCC, the average sea level is expected to rise by 18-59 cm in 2090-2099 relative to 1980-1999; however, more recent estimates indicate an accelerated melting of ice and a range between 50 and 140 cm in the same time period. Given all the uncertainties, people may prefer to take a risky approach, that is, wait-and-see rather than act now on climate mitigation.
Experiences of climate change in the real world are much delayed and uncertain, and exposure to realistic climate consequences can vary considerably from individual to individual. Thus, day-to-day experiences do not always agree with the scientiﬁc predictions of future climate consequences: when there is two feet of snow on the ground, a person perceives the threat of climate change as far-off. For example, the 2010 ‘snowmageddon’ in Washington, DC was sufficient for several congressmen to set back progress on an energy and climate bill pending legislation in Congress. Furthermore, given the uncertainties and complexity of the earth’s climate, people seem to rely more on their recent day-to-day experiences, rather than on the scientiﬁc predictions and written descriptions about the catastrophic consequences of climate change in the future. This behaviour is supported by recent ﬁndings suggesting that as the complexity of a problem increases, people rely more on their own experience rather than on a written description of a risky situation.
For policymaking, uncertainties for earth’s climate are communicated using both descriptive and experiential methods. The descriptive methods include detailed climate models, newspaper reports, or other institutional reports (such as a news item in a newspaper or the IPCC report). The experiential methods include personal day-to-day experiences gained through movies, or experiences gained through video games (movies like An Inconvenient Truth or The Day After Tomorrow). Although both the descriptive and experiential methods seem to be common, decisions made from experience or description on climate change seem to have fallen on deaf ears. A large number of people, including citizens, policymakers, and scientists, prefer to take risks and wait, rather than act now to reduce emissions, that is, they exhibit a risk-seeking behaviour for climate change.
There is evidence that the use of descriptive and experiential methods seem to create differences between economists and climate scientists on policy estimates about the cost, timing, and probability of future climate consequences. For example, according to William Nordhaus, Sterling Professor of Economics at Yale University, when economists from the National Academy of Sciences (NAS) were asked to assess the cost of damages in gross world product (GWP) for a rapid six degrees Celsius rise in average earth’s temperature by 2090, the estimates varied between 0.8 per cent of GWP (for economists) and 62 per cent of GWP (for climate scientists).
Similarly, when the same people were asked to assess the probability of damages occurring under the same scenario, estimates varied between 0.3 per cent (for economists) and 95 per cent (for climate scientists). Moreover, the study admitted to being uncertain about the timing of climate consequences and gave different scenarios to the NAS panel. For example, one scenario was projected more than 100 years from now in the year 2175, and another less than 100 years from now in the year 2090. Generally, the economists’ predictions seem to underweight the cost and probability, whereas the natural scientists’ predictions seem to overweight the same cost and probability. According to Nordhaus, the climate scientists’ overweighting was due to their widespread exposure to descriptive models of climate change; whereas, economists’ underweighting was driven by their widespread reliance on their present experiences of climate change in the absence of descriptive climate knowledge. In fact, recent research in judgment and decision making (JDM) has revealed that decisions made from a description overweight low probability consequences; whereas, decisions made from experience underweight low probability consequences. This JDM finding seems to be robust in a large class of day-to-day decisions, including those for our environment.
So what’s the bottomline? Given these real-world evidences, systematic research is needed that could evaluate the influence of descriptive and experiential probability of climate consequences in combination with their cost and timing on people’s risk-seeking behaviour. Thus, the effects of communicating the uncertainties in cost, timing, and probability of climate consequences through descriptive and experiential methods on people’s risk-seeking behaviour is less understood and needs to be systematically investigated.
(The writer is on the faculty of Indian Institute of Technology, Mandi, India)