James Q. Wilson used to like to tell social scientists, “Stop trying to predict the future; you can’t even predict the past!” A slightly more refined version of this axiom, which I first heard explained by John DiIulio—one of Wilson’s protégés, is that our social science methodology has gotten very good at explaining 150 percent of the variance of many social phenomena.
This insight probably applies to climate science as well as social science. Yes, yes—let’s acknowledge with obligatory snark that too much of climate science is actually “social,” that is, “political,” in character. But The Economist notes this week (“Who Pressed the Pause Button?”) that the frantic attempts to explain the current 15 year “pause” in global warming climate change look to have overexplained it. And if you’ve overexplained something, your grasp of the matter is probably defective.
[A]ttempts to explain away that stable average have not been convincing, partly because of the conflict between flat temperatures and rising CO2 emissions, and partly because observed temperatures are now falling outside the range climate models predict. The models embody the state of climate knowledge. If they are wrong, the knowledge is probably faulty, too. Hence attempts to explain the pause. . .
The IPCC and its circle offer four explanations which are not necessarily mutually exclusive: solar variation, deep ocean heating, aerosols, and (the new one to me) abnormally high Pacific trade winds. The Economist briefly summarizes each of these ideas.
Meanwhile, our friends at the Global Warming Policy Foundation over in London have just released a useful report on the matter: A Sensitive Matter: How the IPCC Hid the Good News on Global Warming. The authors argue that within the IPCC’s own report is convincing evidence—drawn from the peer-reviewed scientific literature—that climate sensitivity to greenhouse gases is much lower than previously thought, making climate change a problem of moderate dimensions at worst. From the summary:
The scientific part (WGI) of the fifth IPCC assessment report (AR5), published in final form in January 2014, contains some really encouraging information. The best observational evidence indicates our climate is considerably less sensitive to greenhouse gases than climate scientists had previously thought. The clues and the relevant scientific papers are all mentioned in the full IPCC report. However, this important conclusion is not drawn in the full report – it is only mentioned as a possibility – and is ignored in the Summary for Policy- makers (SPM).
Until AR5, for 30 years the scientific establishment’s best estimate and their uncertainty range for climate sensitivity had hardly changed. The best estimate for equilibrium climate sensitivity (ECS) started and ended at 3◦C and the uncertainty range generally had a lower bound of 1.5◦C and an upper bound of 4.5◦C. However, several recent studies give best estimates of between 1.5◦C and 2◦C, substantially lower than most earlier studies indicated.
If you don’t have time for the full GWPF study, Cato’s Patrick Michaels and Chip Knappenberger offer the best short treatment here and here. Here’s their killer paragraph:
[C]limate models have consistently overestimated the amount of warming that has taken place. In fact, they are so bad, that over the course of the past 25 years (and even at some lengths as long as 35 years) the observed trend falls outside of the range which includes 95 percent of all model runs. In statistical parlance, this situation means that the observed trend cannot be reliably considered to be part of the collection of modeled trends. In other words, the real world is not accurately captured by the climate models—the models predict that the world should warm up much faster than it actually does.
I think the greatest climate sensitivity right now is with the Climatistas who see the whole thing slipping away from them; hence the hectoring, panicky speeches of John Kerry. You don’t need a model to detect or predict this.
Bonus! The Senate is going to pull an all-nighter next week to talk about . . . climate change. You know they’re desperate when they’re going after the insomniac audience on C-SPAN.
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