Fears about Polar Bear Populations Are Refuted by Scientific Forecasting

Published July 1, 2008

Who doesn’t like polar bears? They’re cute and cuddly and lend themselves to heart-melting images.

So when the federal government commissioned studies last year to support the listing of polar bears as a threatened or endangered species, the project was greeted with near-universal acclaim. Those studies concluded the current growth trend in the polar bear population will reverse and the bears’ population will decrease substantially in the future.

The U.S. Department of Interior relied on such studies in its May 2008 decision to list the polar bear as a threatened species under the Endangered Species Act.

Government Forecasts Flawed

However, when I joined forces with a prominent forecasting expert and one of the world’s leading climate scientists to audit the government’s forecasts, we found the predictions were based on false assumptions and violated many principles of scientific forecasting. In fact, we found the government forecasters followed less than one-sixth of the relevant principles of scientific forecasting.

The bottom line is that the government studies are irrelevant to the question whether polar bears are endangered or threatened.

The audit–in which I was joined by Kesten Green of Monash University and Willie Soon of the Harvard-Smithsonian Center for Astrophysics–has been accepted for publication in the management science journal Interfaces. It is the only peer-reviewed paper on polar bear population forecasting that has been accepted for publication in an academic journal.

Scientific Principles Ignored

Decision makers and the public should expect people who make forecasts to be familiar with the scientific principles of forecasting, just as a patient expects his physician to be familiar with the procedures dictated by medical science.

Our research regarding polar bear populations shows the best forecast is that numbers are equally likely to rise as to fall. The polar bear population has been increasing over recent decades, and a continuation of that trend over the short term is quite possible.

Scott Armstrong ([email protected]) is a professor at the Wharton School at the University of Pennsylvania.

For more information …

Scott Armstrong, Kesten Green, and Willie Soon, “Polar Bear Population Forecasts: A Public-Policy Forecasting Audit,” Interfaces, forthcoming: http://publicpolicyforecasting.com