The Learned Conservatism of Climate Scientists

Despite the right-wing narrative that climate scientists are ginning up their predictions of doom because they hate capitalism and America or something (seriously, I never understood why people would believe that climate activists and scientists want to be right–I’d love to be wrong about this!), the reality is that the scientists are in fact too conservative in their statements, as this essay by Dale Jamieson, Michael Oppenheimer and Naomi Oreskes argues.

Although the results of climate research have been consistent for decades, climate scientists have struggled to convey the gravity of the situation to laypeople outside their field. If anything, the wider public only recently seems to have awakened to the threat of the climate crisis. Why?

In our new book, Discerning Experts: The Practices of Scientific Assessment for Environmental Policy, we attempted to illuminate how scientists make the judgments they do. In particular, we wanted to know how scientists respond to the pressures, sometimes subtle, sometimes overt, that arise when they know that their conclusions will be disseminated beyond the research community – in short, how scientists are affected when they know the world is watching.

We explored these questions with respect to assessments of acid rain, ozone depletion and sea level rise predictions from the west Antarctic ice sheet.

While climate skeptics and deniers often accuse scientists of exaggerating the threats associated with the climate crisis, the available evidence suggests the opposite. By and large, scientists have either been right in their assessments, or have been unduly conservative. We noticed a clear pattern of underestimation of certain key climate indicators, and therefore underestimation of the threat of climate disruption. When new observations of the climate system have provided more or better data, or permitted us to re-evaluate earlier conclusions, the findings for ice extent, sea level rise and ocean temperature have generally been worse than previously thought.

One of the factors that appears to contribute to this trend of underestimation is the perceived need for consensus, or what we call “univocality”: the felt need to speak in a single voice.

Many scientists worry that if they publicly air their disagreement, government officials will conflate their differences of opinion with ignorance and use this as justification for inaction.

Others worry that even if policy-makers want to act, they will find it difficult to do so if scientists fail to send an unambiguous message. Therefore, scientists actively seek to find their common ground, and to focus on those areas of agreement. In some cases, where there are irreconciliable differences of opinion, scientists may say nothing, giving the erroneous impression that nothing is known.

How does the pressure for univocality lead to underestimation? Consider a case in which most scientists think that the correct answer to a question is in the range one to 10, but some believe that it could be as high as 100. In this case, everyone will agree that it is at least one to 10, but not everyone will agree that it could be as high as 100. Therefore, the area of agreement is one to 10, and this will be reported as the consensus view. Wherever there is a range of possible outcomes that includes a long, high-end tail of probability, the area of overlap will lie at or near the low end.

I can hardly blame a scientist for being conservative in their claims. But despite the popular belief of science being pure and true, it doesn’t exist in a vacuum and is always influenced by both the times and by the individuals engaging in it. So that they would be more conservative because of fear of bad publicity is hardly surprising. It is however distressing given the reality of the crisis, merely the greatest in the history of the planet.