In a new essay, researchers dismantle a common form of climate skepticism: defending inaction on climate change by citing lingering uncertainties in climate models and in other scientific evidence of the mounting crisis.

This tactic of using uncertainty as an excuse to stall policy action on global warming is often politically motivated and driven by self-interest, say the essay's authors, led by a senior scholar at the National Academies of Sciences, Engineering and Medicine. The authors use the label "neoskeptics" to describe people or companies that have shifted the uncertainty debate in this way.

The best way for climate experts to respond, they say, is to focus more on areas of science that expose the true costs of inaction. They cite a growing body of peer-reviewed work in the disciplines of decision science and risk management.

"Although neoskeptics claim to accept the reality" that humans are changing the climate, "their inference that inaction is justified seriously under-emphasizes some well-established characteristics of [man-made climate change] that are important for informing choices," the authors wrote.



These characteristics are: "that the risks of extreme and damaging outcomes are continually increasing, so that waiting for certainty has increasing costs; that inertia in the system may result in its crossing major tipping points without timely warning; and that there is value to insuring against worse cases, especially when they are likely to be worse than those of the past."

When it comes to climate change, "there will always be some sort of uncertainty," said Paul Stern, lead author of the article, published this week in the journal Science. "You can't justify inaction forever on those grounds." Stern added that uncertainty hasn't stopped people from responding to a host of other issues, from terrorism to infectious diseases.

Stern wrote this essay with three academics from The Evergreen State College in Washington, the University of California, San Diego and the University of Illinois, Urbana-Champaign.

According to Stern and his colleagues, those who defend business as usual—whether for climate change or other issues—often follow the same pattern. Initially, they deny outright or question new scientific findings that justify change. Then, as the evidence against them mounts, they start to question the severity of the problem and argue that as long as some uncertainty exists, the smartest and financially shrewd move is to do little or nothing.

The misuse of uncertainty as a justification for inaction has a long history, said Stephan Lewandowsky, a cognitive scientist at the University of Bristol who was not involved in the essay. "Whenever there is any scientific finding that impacts vested interests, then uncertainty will be trotted out as the reason for opposing the science. That's been true for tobacco; true for the ozone hole."

There's even a term for it: scientific certainty argumentation methods, or SCAMs. The sociologist William Freudenburg coined the acronym in 2008 "with the pun intended," said Lewandowsky.

Some members of the climate community have been aware of—and warned against—the uncertainty fallacy for decades.

In April 1980, a climate scientist spoke to members of Congress about this issue. "In our view, it is extremely important to realize that decision-makers cannot indefinitely delay taking actions [on rising carbon dioxide levels] because of very real geophysical uncertainties," William Kellogg, then a researcher at the National Center for Atmospheric Research, told the Senate Committee on Energy and Natural Resources.

Even Pope Francis, in his encyclical released last summer, cautioned against using the excuse of uncertainty to put off action on climate change.

According to Lewandowsky, the uncertainty argument doesn't square with reality. "Uncertainty isn't your friend," said Lewandowsky, whose own research has shown "that greater uncertainty means greater risk."

Although the recent essay strongly criticizes the neoskeptics, the authors wrote that focusing attention on climate uncertainty raises important questions.

Using decision-making science as a guide, the essay authors give some examples of smart responses to climate change such as putting in place a wide range of policies to ensure at least some will work and choosing policies that are flexible and can adapt depending on the climate situation. These approaches have been embedded in the authoritative scientific consensus and in mainstream scientists' recommendations for policymakers for at least 15 years.

"Managing and reducing risk has absolutely been at the core of the way the broader scientific community, and especially the Intergovernmental Panel on Climate Change, has addressed this issue" for years, said Chris Field, a Carnegie Institution director, who was not involved with the essay. "This is not a new concept."

"A risk-based process to climate change is absolutely key," said John Reilly, an economist at MIT who did not contribute to the essay.

The authors offer a medical analogy: Patients diagnosed with hypertension can benefit from changing their diets or exercising without knowing how much change they need to avoid a stroke or heart attack.

But according to Reilly, this metaphor doesn't capture the challenge faced by any one city, state or region because while they can contribute to climate action, they can't alone stop what is a global problem.

The essay's authors don't claim that theirs will be the last word.

"We do not presume that empirical analysis of risks, techniques for informing decisions under uncertainty, or better ... models will end skepticism, neo- or otherwise, about climate change," they wrote. "Some skepticism is motivated by ideological and financial interests tied to the continued use of fossil fuels, and debates will continue over the risks and how best to manage them."