A January 13 article in Scientific American attempted to undermine a statement by Rex Tillerson during his confirmation hearing. In answer to a question, he said, “said “our ability to predict” the effect of increased greenhouse gas concentrations in the atmosphere “is very limited.” Scientific American asserts, “That’s not entirely accurate. Beyond defining its own interpretation of the meaning of “is very limited”, the article conflates a scientific fact with professional judgment and computer model outputs to reach a conclusion that is not valid.
Scientific American makes the point that scientists “ability to make predictions based on a particular theory corresponds to the number of times they’ve verified that theory using different lines of evidence: The more verification, the more likely it is that their predictions will turn out to be accurate. To start, scientists have verified the theory of the greenhouse effect, which says that gases like CO2 trap the sun’s heat. It then states the obvious that the warming potential of CO2 “is no longer a matter of prediction.”
There is no disagreement that CO2 is a greenhouse gas and contributes to the planet’s warming. Without it, the average temperature would be below freezing. Beyond the fact that CO2 warms the planet, there is no evidence that the professional judgment of climate scientists and advocates is a good proxy for scientific facts concerning the climate system. And, the models that predict significant warming– that has not occurred over past 20 years– include assumptions that have not been validated. That helps to explain why the models do so poorly.
Physics has established that the warming potential of CO2 is non-linear which means that the warming associated with the next increment to the atmospheric concentration of CO2 is less than the one that preceded it. For CO2 emissions to be responsible for more than half of the warming that has occurred over the past 50 years, it would be necessary for climate sensitivity to be much greater than any empirical evidence suggests is likely.
The statements made by Scientific American concerning warming over the past 50 years are based on the subjective probabilities and professional judgment of scientists who participate in the IPCC process. Scientific American would do well to explore the research foundation of Group Think as well as the work of Daniel Kahnamen and Amos Tversky who demonstrated the biases that influence even the most capable. In short, we are not as rational as we think. Michael Lewis’ most recent book The Undoing Project is a good introduction to Kahnamen and Tversky research.
Scientific American cites the high confidence of scientists that “global warming will lead to changes in the climate, including a rise in extreme weather events and sea levels. This is also no longer a matter of prediction”. Again, that statement is based on professional judgment, not established science. Carl Wunsch, one the world’s leading oceanographers, stated some years ago that sea level has been rising since the end of the last ice age, almost 20,000 years ago, and will continue to rise until the next one. The understanding of the human contribution is in its early stages because advances in measurement technology have been in place only a little over a decade.
The claims about extreme weather are pure advocacy rhetoric as has been shown by the work of Professor Roger Pielke In testimony before the U.S. House of Representatives where he made the following summary points: “There exists exceedingly little scientific support for claims found in the media and political debate that hurricanes, tornadoes, floods and drought have increased in frequency or intensity on climate timescales [periods of the 30-50 years and longer] either in the United States or globally. These conclusions are supported by a broad scientific consensus, including that recently reported by the Intergovernmental Panel on Climate Change (IPCC) in its fifth assessment report”.
Since its series of attacks on Bjorn Lomborg’s The Skeptical Environmentalist in 2002, Scientific American has continued to demonstrate that Wall Street Journal columnist James Taranto was probably correct in labeling it a “a liberal political magazine.” It’s treatment of Rex Tillerson’s comments on climate change was political journalism.