July 19, 2004

Fraser Institute queries usefulness of climate computer models as basis for policy decisions

A new study by the Vancouver-based Fraser Institute casts doubt on the usefulness of computerized climate models in aiding the development of public policy relating to climate change, particularly with regard to policy decisions as critical as Canada's ratification of the Kyoto Protocol. The paper, titled "The Science Isn't Settled: The Limitations of Global Climate Models," argues that current global climate models have two significant limitations on their use.

First, climate trends using any source of observed data, including surface stations, weather balloons and satellites, are uncertain due to the short length of the records and the need for adjustments to correct for artificial discontinuities such as instrument or satellite changes.

The second limitation is that future climate trends are projected, not by simply extrapolating recent trends, but by using climate models with deficiencies which make the projected trends very unreliable.

"Climate models oversimplify many poorly understood climate processes and results from the models can be contradictory," said study author Dr Kenneth Green, who is the Institute's director of risk, regulation and environment studies. "Clearly, the data generated does not provide a meaningful foundation on which to base sound public policy decisions, especially something as significant as the decision to ratify Kyoto."

Green calls for a complete re-examination of the science of climate change, recognizing that some climate changes (both natural and human-caused) are climate surprises, or events that are not anticipated in advance (and, by definition, are not properly incorporated into models). Accordingly, says the study, policy should not be grounded in the output of computer models of limited utility.

Green makes a number of other recommendations which he says will provide a "reality check" on the science of climate modeling. He says scientists and decision-makers should acknowledge that published scenarios of future greenhouse gas concentrations are skewed toward unlikely high growth in emissions; therefore, climate models using these scenarios will tend to project an unrealistically high degree of warming. They should also acknowledge that models cannot accurately predict the absolute amount of warming (or other climate change) resulting from a particular scenario of greenhouse gas concentrations.

The study recommends that full and transparent economic and risk analyses be performed of the costs and effectiveness of proposed greenhouse gas control actions, including alternatives. It calls for the redirection of some resources away from greenhouse gas controls, reduction and mitigation toward:

research efforts to improve the state of weather and climate forecasting;

researching probabilities of different climate change outcomes; and

research programs that will help Canadians adapt to climate change regardless of origin.

The study may be viewed on the Fraser Institute Web site, www.fraserinstitute.ca. More information is available from Dr Kenneth Green, 604/714-4547, E-mail: keng@fraserinstitute.ca.

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