In a Wall Street Journal op-ed, Richard McNider and John Christy push thinly sourced, out-of-context claims about the success of climate models to argue that we really don’t know whether human-caused warming is a problem. They fancy themselves modern-day Galileos, when actually their argument reflects the vestiges of a half-century-old view that is falling to the once-novel but now steadily growing scientific evidence for climate change. Michael MacCracken: "McNider and Christy are blowing smoke."
The following is a guest post by Climate Nexus (text in PDF format here):
McNider and Christy Style Themselves Revolutionary But Defend Inertia
In a Wall Street Journal op-ed, Richard McNider and John Christy push thinly sourced, out-of-context claims about the success of climate models to argue that we really don’t know whether human-caused warming is a problem. They fancy themselves modern-day Galileos, when actually their argument reflects the vestiges of a half-century-old view -- one that is falling to the once novel but now steadily growing scientific evidence for climate change.
These long-time climate doubters inflate minor points of dispute to suggest that models are “spectacularly wrong” and “0 for 10.” But over the long term, climate models have been right on target, and we have a wealth of evidence supporting the picture they paint of the dangers of unmitigated climate change.
One of the few science sources named in the WSJ article is the 2012 State of the Climate report published by NOAA. However, Christy and McNider apparently chose to ignore the main findings from that report, including the continuation of warming trends at the Earth surface, sea surface, upper ocean, and deep ocean. The most recent IPCC report found that, while variations exist on the scale of 10-15 years, over the long term models closely reproduce observed trends for both surface and upper ocean temperatures. The State of the Climate report also notes the observed long-term cooling of the stratosphere, just as climate models predict (and a result that only occurs when human influence is incorporated into the models of the Earths’ climate).
From this comprehensive overview the climate models seem to be doing quite well. But Christy and McNider assert that we should be ignoring these indicators, and instead hinge everything only on mid-tropospheric warming, “the fundamental sign” of climate change. They don’t explain why mid-tropospheric warming is fundamental, and in fact there is much less evidence for the significance of mid-tropospheric temperatures than there is for other indicators. This is part of the reason why mid-tropospheric temperatures aren’t part of the top-line findings of the 2012 State of the Climate report. As for the tropospheric temperature record:
- Compared to the surface temperature record, the mid-troposphere record is almost a century shorter, and subject to disruption by changes in measurement technology and methods. Past studies have repeatedly found issues with the techniques used to calibrate temperatures between measuring systems.
- Studies have also found that the increased cooling of the stratosphere has masked tropospheric warming in some satellite channels. When the effect of the stratospheric cooling is removed, tropospheric warming appears close to model predictions.
- Another 2011 study on tropospheric warming concluded, “the magnitude of the trend significantly depends on the data sources… In general, greater consistency is needed between the various data sets before a climate trend can be established” in a trustworthy way.
- A 2012 study found the discrepancy Christy and McNider mention, but was unable to establish whether it was due to biases in the models, datasets, or both.
Contrary to Christy and McNider’s implication in the WSJ, scientists aren’t suppressing discussion about the mid-troposphere. In fact, they’re actively participating. But they are not suggesting that the question of what’s happening at 18,000 feet upends the body of climate knowledge they’ve been building on for a century. The IPCC is fully aware of the questions about the troposphere, yet still places its estimate of climate sensitivity within a range of 1.5-4.5ºC. Three degrees of sensitivity would be enough to cause catastrophic impacts by the end of the century. The lowest end of the range just means a few more years of delay before the same impacts take place. And the high end remains an equally likely possibility, which is why the world’s scientists remain quite concerned about the climate:
“In order to properly plan for the coming climate change, policymakers rely on scientific estimates about how much warming can be expected this century. These estimates are based on 1) centuries old physics 2) historical data spanning hundreds of thousands of years and 3) climate models which use well-understood physics and a wealth of actual observations. All three of these tell us that the planet will dangerously warm if humans keep emitting record amounts of heat-trapping gases.
"Contrary to what Dr. Christy states, climate models have done a very good job at projecting the warming that has already been observed and that is why there is confidence they will continue to be accurate in the future. We should heed the advice of the late Dr. Sherwood Rowland who said (referring then to ozone depletion): ‘What's the use of having developed a science well enough to make predictions if, in the end, all we're willing to do is stand around and wait for them to come true?’”
“Comparing the average temperature trend at the surface to the average trend from 0 to 75,000 feet (which dilutes the warming trend of the troposphere with the cooling trend of the stratosphere) will, of course, give different results. What matters to people and ecosystems is primarily what happens at the surface and that temperature trend is increasing, as made very clear by the shifting ranges of flora and fauna in addition to the melting glaciers and ice sheets, rising sea level, and more.
"Yes, the observed rate of warming over the last decade is a bit less than is projected were the only factor acting the rising concentration of greenhouse gases, but these other factors that seem to be restraining the rate of warming are very short-term (e.g., volcanic cooling persists only a few years after an eruption, and cooling resulting from the sulfur dioxide from power plants lasts only as long as the emissions persist); by contrast, increasing the atmospheric CO2 concentration will leave a substantial increase even well after a thousand years. McNider and Christy are blowing smoke.
"The sensitivity of the climate to increasing concentrations of greenhouse gases is not determined solely by models and theoretical calculations—the general magnitude of the climate sensitivity can also be derived by analyzing Earth’s climate history—so just the type of data-based analysis that McNider and Christy favor. With the low climate sensitivity suggested by McNider and Christy, there is no way to explain how the period of the dinosaurs could have been so warm, nor is there a way to explain how the period 20,000 years ago could have had an ice sheet covering most of North America north of the Ohio River Valley in a mile or two of thick ice.”
“Skeptics McNider and Christy try to wear the mantle of Galileo in the pages of the Wall Street Journal. Alas, to do so they must first stop making silly mistakes. Peer-reviewed comparisons between data and models show that the models do a good job of simulating the observations. McNider and Christy's non-peer-reviewed comparison showing poor agreement requires flagrant cherry picking. In the end, like most scientific outliers, their ideas are destined for the dustbin of science.”
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UPDATE February 21 -- also see these excellent posts:
Joe Romm at Climate Progress, Scurvy Story: Why You Should Believe 97% Of Climate Scientists, Not Long-Wrong John Christy
Dana Nucitelli in The Guardian: Nazis, shoddy science, and the climate contrarian credibility gap
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Earlier Climate Nexus guest posts on climate change misinformation and disinformation in the Wall Street Journal: