Forecasting global warming

One of the world´s foremost authorities of scientific forecasting, professor J. Scott Armstrong slams the alarmism of the IPCC global warming scenarios in a letter to the Wall Street Journal:

Bjorn Lomborg ("Can Anything Serious Happen in Cancun?", op-ed, Nov. 12) claims that government spending on global warming policies is wasted, but he assumes that global warming caused by carbon dioxide is a fact. It is not. We base this statement not on the opinions of 31,000 American scientists who signed a public statement rejecting this warming hypothesis (the "Oregon Petition"), but rather because the forecasts of global warming were derived from faulty procedures.

We published a peer-reviewed paper showing that the forecasting procedures used by the U.N.'s Intergovernmental Panel on Climate Change violated 72 of 89 relevant principles (e.g., "provide full disclosure of methods"). The IPCC has been unable to explain why it violated such principles. In response, we developed a model that follows the principles. Because the climate is complex and poorly understood, our model predicts that global average temperatures will not change.
In testing the models on global temperature data since 1850, we found that the long-range (91-to-100-years ahead) forecast errors from the IPCC's projection were 12 times larger than the errors from our simple model.
Mr. Lomborg concludes there are better ways for governments to spend the funds devoted to global warming. We suggest this money should instead be returned to taxpayers.

http://online.wsj.com/article/SB10001424052748703326204575616983641995488.html

PS
It will not be easy for the climate alarmists to ignore professor Armstrong´s opinion. His credentials are rather strong:

Professor Armstrong is internationally known for his pioneering work on forecasting methods. He is author of Long-Range Forecasting, the most frequently cited book on forecasting methods, and Principles of Forecasting, voted the “Favorite Book – First 25 Years” by researchers and practitioners associated with the International Institute of Forecasters.