(August 22, 2013) Top economist, a true believer in global warming, proves predictions of catastrophe are meaningless.
By Lawrence Solomon for the National Post, published August 22, 2013All predictions of global warming doom and destruction rest on meaningless computer models, say climate change skeptics such as Freeman Dyson, America’s best-known scientist, and Antonino Zichichi, Italy’s best-known scientist. They and other skeptics looked at models touted as reliable and declared them meaningless.
Now these unabashed skeptics are joined by an unabashed true believer in rising sea levels, greater climate variability and other perils associated with global warming: Robert S. Pindyck, a physicist, engineer and Professor of Economics and Finance at MIT’s Sloan School of Management. Pindyck dissected a “plethora” of climate change models and found that they “have crucial flaws that make them close to useless as tools for policy analysis … [these] analyses of climate policy create a perception of knowledge and precision, but that perception is illusory and misleading.”
Pindyck’s dissection of the work of the world’s climate modelers — these are the people associated with the IPCC and other organizations who bring us dire predictions — is contained in a study to be published in the Journal of Economic Literature, and recently published by the National Bureau of Economic Research (NBER).
His study is entitled “Climate Change Policy: What Do the Models Tell Us?” He provides the answer in a two-word sentence that immediately follows: “Very little.” This is an uncharacteristically blunt assessment coming from a publication of the NBER, the most authoritative organization in its field — it is the NBER which officially decides when the U.S. has entered or left a recession, for example.
The blunt talk pervades his study — 21 pages that methodically eviscerate any pretence that the climate change modellers have produced anything that anyone, anywhere can rely on for any decision requiring more authority than would be provided by a Ouija board.
Pindyck starts by describing the many efforts of scientists to construct models that integrate climate science with the impact of greenhouse gas emissions, calling this “a growth industry” that “even has its own journal, The Integrated Assessment Journal.” Try as they might, though, all the modellers’ efforts to produce reliable estimates proved futile. Pindyck breaks down the climate models — they’re called integrated assessment models, or IAMs for short — into six constituent parts and concludes that, because they’re all-but-useless, “climate change policy can be better analyzed without the use of IAMs.”
Why are they useless? For one thing, the “modeler has a great deal of freedom in choosing [his inputs]. Thus these models can be used to obtain almost any result one desires.” To highlight the absurdity of this freedom, Pindyck mentions that a “colleague of mine once said ‘I can make a model tie my shoe laces.’”
There’s more. When you look into “the guts of the models,” Pindyck explains, a pseudo complexity becomes evident: “for some of the larger models, the ‘guts’ contain many equations and can seem intimidating. But in fact, there are only two key organs that we need to dissect.”
The first of these organs is “climate sensitivity,” or the temperature increase that would come of a doubling of man-made CO2 levels. “Here is the problem,” he explains. “The physical mechanisms that determine climate sensitivity involve crucial feedback loops [whose effect, if any, is] largely unknown, and for the foreseeable future may even be unknowable.”
A colleague of mine once said ‘I can make a model tie my shoe laces’
Pindyck then laces into the second key organ in the models, the “damage function” which describes how much damage higher temperatures might do. Here the modelers again “know almost nothing, so developers of IAMs can do little more than make up functional forms and corresponding parameter values. And that is pretty much what they have done. … The bottom line here is that the damage functions used in most IAMs are completely made up, with no theoretical or empirical foundation. … [making it] a completely meaningless exercise.”
Heaping ridicule on the methodology of the modelers, Pindyck refers to an IPCC survey of 22 peer-reviewed published studies of climate sensitivities that was summarized into a meaningless graph. The modelers then used this IPCC graph in their subsequent models. “But where did the IPCC get those numbers? From its own survey of several IAMs. Yes, it’s a bit circular.”
Because the models all provide sham estimates, Pindyck advocates throwing them out and taking our best shots at answers. “Perhaps the best we can do is come up with rough, subjective estimates of the probability of a climate change sufficiently large to have a catastrophic impact … Of course this approach does not carry the perceived precision that comes from an IAM-based analysis, but that perceived precision is illusory.”
Lawrence Solomon is executive director of Energy Probe and author of The Deniers.