Consensus Can Be Bad for Climate Science

Published January 1, 2005

British Prime Minister Tony Blair has complained about the failure of countries to reach agreement on scientific evidence of the human-made portion of global warming, which he views as incontrovertible and disastrous.

A British government spokesperson was quoted as saying, “Until we get consensus on the science we will never get a consensus on the rapid action needed before it’s too late.”

Proponents of dramatic action on climate are calling for “consensus” among scientists on the issue of global climate change in order to convince policymakers that the United States should immediately and sharply curb carbon dioxide and other greenhouse gas emissions as the promised means to prevent disastrous climate change.

Consensus Not Scientific

Scientific agreement, though, differs distinctly from consensus wrought by social-political pressures. Efforts to force a consensus are pernicious to science. The body of evidence and facts on which scientists agree–as currently known–must always be challengeable by new information. That is the basis of the scientific method.

An upcoming paper in Environmental Science & Policy sheds some light on the distortion of climate science by “consensus” politics. Daniel Sarewitz of Arizona State University, who was on a panel that authored a 2003 climate report for the National Academies of Sciences’ National Research Council (NRC), provides an inside view of the NRC report’s publication process and details what outsiders may get as the “consensus.” It isn’t what most people would expect from a scientific body.

The NRC report introduced the need for continued research: “The consensus view of scientists is that human activities are changing Earth’s climate and that this could have very important consequences for human life and natural ecosystems.”

That made sense. Most scientists agree that carbon dioxide concentration has increased by approximately 30 percent in 200 years because of human activities. And they agree that, all things being equal, the addition of greenhouse gases to the air should cause some warming.

More Research Needed

The big questions, which can be answered only by science, are: How much warming, and when? To get accurate answers–pinning down the meaning of “could have very important consequences”–involves tackling uncertainties in the scientists’ climate forecasts.

Thus, the charge to the NRC panelists also was sensible, as it was embodied by the title of the draft report: “Climate Change Feedbacks: Characterizing and Reducing Uncertainties.” Climate is a complex and non-linear system, involving “feedbacks”–for example, clouds, ocean currents, plants–that may amplify or dampen initial perturbations into disproportionate outcomes, large or small. Scientists remain highly uncertain of the precise workings of many of those physical processes, and reducing uncertainty is essential to gaining accurate climate forecasts.

But along the way, discussion on research uncertainties was shifted to an insistence that science should look as tidy as possible–a social consensus. As Sarewitz notes, the final NRC report title omitted the highlight on uncertainties and read merely “Understanding Climate Change Feedbacks.”

One certainty in science is that all its results are uncertain; achieving better accuracy means reducing uncertainty, but always within limits. Progress comes from tension among hypotheses, equipment and instruments for observing and measuring, experimental results, and evidence, with scientists acting as unique mental rebels. Columbia University sociologist Robert K. Merton (1910-2003) noted, “Most institutions demand unqualified faith; but the institution of science makes skepticism a virtue.”

Immune to Social Consensus

The convenience of quiet consensus is in opposition to the structured, skeptical rebelliousness of the scientific method, which strikes at uncertainty by trying to reduce it.

Michael Crichton, author of Jurassic Park and creator-producer of ER, recently remarked, “Consensus is the business of politics. If it’s consensus, it isn’t science. If it’s science, it isn’t consensus. Period.”

Right now, tremendous uncertainty exists in answering important questions about climate. Physical law is not made by social consensus, only by scientific evidence, which comes from acknowledging those things we know as uncertain or even unknown–not accepting as incontrovertible that which is still unproven.

Willie Soon ([email protected]) is a physicist at the Solar, Stellar, and Planetary Sciences Division of the Harvard-Smithsonian Center for Astrophysics and an astronomer at the Mount Wilson Observatory. He is also science director for Tech Central Station.

Sallie Baliunas, Ph.D. ([email protected]) served as deputy director of Mount Wilson Observatory and as senior scientist at the George C. Marshall Institute in Washington, DC, and chairs the Institute’s Science Advisory Board.