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MIT's unscientific, catastrophic climate forecast
...The Financial Post asked us to look at a report last month from the Massachusetts Institute of Technology (MIT) Joint Program on the Science and Policy of Global Change, titled "Probabilistic Forecast for 21st Century Climate based on uncertainties in emissions (without policy) and climate parameters."

The MIT report authors predicted that, without massive government action, global warming could be twice as severe as previously forecast, and more severe than the official projections of the United Nations' Intergovernmental Panel on Climate Change (IPCC). The MIT authors said their report is based in part on 400 runs of a computer model of the global climate and economic activity.

While the MIT group espouses lofty-sounding objectives to provide leadership with "independent policy analysis and public education in global environmental change," we found their procedures inconsistent with important forecasting principles. No more than 30% of forecasting principles were properly applied by the MIT modellers and 49 principles were violated. For an important problem such as this, we do not think it is defensible to violate a single principle.

For example, MIT forecasters should have shrunk forecasts of change in the face of uncertainty about predictions of the explanatory variables; in this case the variables postulated to influence temperatures. More generally, they should also have been conservative in this situation of high uncertainty and instability. They were not....

...When one looks at long series of Earth's temperatures, one finds that they have gone up and down irregularly, over long and short periods, on all time scales from years to millennia. Moreover, science has not been able to tell us why. There is much uncertainty about past climate changes and about the strength and even direction of causal relationships. To wit, do warming temperatures result in more carbon dioxide in the atmosphere or is it the other way round -- or maybe a bit of both? Does warming of the atmosphere result in negative or positive feedback from clouds? There are many more such questions without answers. All this strongly suggests that a no-change forecast is the appropriate benchmark long-term forecast....