Inaction in face of uncertainty a risky proposition in global-warming conundrum

Inaction in face of uncertainty a risky proposition in global-warming conundrum

BY JADE BOYD
Rice News staff

Few scientific debates have become as politicized as the topic of climate change. And though most climate scientists have reached consensus on some key points in recent years — like the fact that the Earth is warming and that humans are causing some of the warming — scientific consensus has done little to quell the rancorous political debate over global warming.

In a Nov. 2 talk titled ”The Use Of Scientific ‘Uncertainty’ in the Policy Debate Over Climate Change,” Texas A&M University atmospheric scientist Andrew Dessler dissected claims made on both sides of the issue, paying particular attention to the argument that climate science still has too many uncertainties to support policies aimed at reducing greenhouse-gas emissions.

Dessler began his talk, which was sponsored by the Department of Earth Science, by drawing a key distinction between ”positive” claims in climate science, which are amenable to scientific testing, and ”normative” claims that are inherently subjective.

”Normative claims relate to whether something is right or wrong, or just or unjust,” Dessler said. ”Often, as scientists, we tend to think that if we answer the scientific questions and get the science right, then policymakers will know what to do. But policy questions that relate to what we as a society should and should not do are normative questions that cannot be decided with scientific arguments.”

Dessler closely examined the findings of the Intergovernmental Panel on Climate Change (IPCC) that the Earth has warmed over the last century, that most of the warming during the past 50 years is likely due to human activity and that warming this century is likely to accelerate. In a series of side-by-side comparisons between the IPCC’s findings and statements of high-profile climate-change naysayers, including President Bush, novelist

Michael Crichton and scientist Robert C. Balling Jr., Dessler showed that climate-change opponents do not directly attack the IPCC’s scientific arguments.

”Even the sharpest climate critics accept that the Earth is warming and that humans are playing a role, but they are quick to point out that we are not certain how much of the warming is caused by humans,” Dessler said.

He said the argument is often presented that in the face of such uncertainty, society should wait before taking precipitous action that may be unwarranted.

Dessler then delved into a detailed examination of the ways society has chosen to make decisions in the face of uncertainty. With three key examples — convicting defendants of a crime, deciding civil claims between plaintiffs and deciding whether to invade Iraq — Dessler attempted to show how society adjusts its actions based on the consequences of potential errors.

In the case of sending an innocent person to prison, for example, society errs on the side of caution, requiring an overwhelming burden of proof ”beyond a reasonable doubt.” It is inherent that guilty people will go free under this system, but society allows it because the alternative — imprisoning the innocent — is worse.

In the second example, deciding civil damages, society requires a ”preponderance of evidence,” which means there should be an equal chance of an error either way.

In the third example, Dessler read a passage from Ron Suskind’s book ”The One Percent Doctrine,” in which Vice President Dick Cheney stated that if there were even a 1 percent chance of terrorists getting a weapon of mass destruction, the United States was obligated to act as if it were a certainty and invade Iraq to stop it. In this case, Dessler said, even in the face of great uncertainty and with a high probability for error, society chose to act because the potential for harm was so great that not acting was seen as a worse alternative.

In his conclusion, Dessler applied each of these three levels of bias toward action or inaction to curtail greenhouse-gas emissions. In the first example, ”beyond a reasonable doubt,” society chooses not to reduce greenhouse emissions until evidence is presented beyond a reasonable doubt that climate change will have catastrophic consequences. In the other extreme, society applies Cheney’s 1 percent doctrine and chooses to reduce emissions — and suffer the economic consequences of shifting precipitously away from a fossil-fuel economy — if there is even a 1 percent chance that greenhouse warming will radically alter the planet’s biosphere.

In making this comparison, Dessler attempted to show that the first path — inaction in the face of uncertainty — carries more inherent risk for society than does the second.

He was quick to point out that he was still making a normative argument — attempting to say what society should do to avert a potential climate disaster. And though most in the Rice audience clearly supported Dessler’s conclusions, he also offered a lengthy discussion of how special interests, particularly industries that would be impacted negatively by a shift away from a fossil-fuel economy, have taken steps to make sure the public continues to adopt a wait-and-see attitude regarding climate policy.