The IPCC Does it Again

It happened again. Just like in 1995, someone sneaked the New York Times some dramatic revelations from a draft version of the Intergovernmental Panel on Climate Change's (IPCC's) as yet unapproved final assessment of the state of global warming science.

The report, which the IPCC produces every five years, has this time dramatically increased the upper limit of its forecast of the 21st century's temperature increase, from 4.5°C to 6.0°C, the Times reveals.

But the document the IPCC sent out for scientific peer review contained no such number. Indeed, after the scientists reviewed it, the maximum value was 4.8°C. What gives? In a sad repetition of a 1995 fiasco in which the key phrase "the balance of evidence suggests a discernible human influence on global climate" was inserted after the document had circulated among scientific reviewers, the IPCC has changed its report's most crucial conclusion at the 11th hour, after the scientific peer review process had concluded.

Some background: Produced every five years, IPCC climate change reports go through several stages. First, a team of scientists selected by the United Nations writes a "zeroth order draft," the purpose of which is apparently to flesh out as many of the environmentally correct hot buttons as possible and to make sure any research indicating global warming is overblown is buried, if mentioned at all. That all but guarantees the next step, scientific review, will be biased. Any criticism levied against this relatively gloomy zeroth draft must therefore argue doubly hard, both against extant text and for a 180-degree revision.

That really isn't peer review in the classic sense, for the IPCC retains "veto power." That is to say, it is up to the original authors to review the scientific comments and decide which to keep and which to ignore. To take a real-life example, say a reviewer suggests the IPCC improve the balance and accuracy of its report by incorporating a January 2000 paper in the refereed journal Climate Research. A paper that proves the late 20th century's warming is inordinately limited to the coldest, deadliest air masses of Siberia and North America. A true peer review process would compel the authors to include that research. The IPCC's response? Bury it in an obscure spot. So much for balance.

After the scientific review process, the IPCC document undergoes a "Government Review." It was at this stage that the 6°C figure was inserted. That's right, after the main scientific review was finished. At the government review stage, readers representing national governments send their comments to those same original authors. But 99 percent of these authors either work for or are funded by those same governments!

This particular brand of inbreeding has a propensity to produce some very strange offspring.

The 6°C figure is based upon a socioclimatological model. For sociology, it relies upon a number of illogical scenarios called "storylines," notions first generated at Columbia University's Center for International Earth Science Information Network (CIESIN). Those "storylines" then generate profiles for the emissions of warming greenhouse gases such as carbon dioxide and purported cooling agents called sulfate aerosols.

Figure 1 shows the socioclimatological ranges of warming that were agreed upon after scientific review, along with the values that were inserted in the government review. It is very clear that this was a major alteration.

Figure 1.  The range of forecast temperatures from the version of the new IPCC report the government reviewers received (light gray shaded region) was expanded in the "government" version someone leaked to the New York Times (bordered by dashed red lines).  The blue line represents the model path most like observed conditions (see "What's Hot").

Those "storylines" can be senseless. "Storyline A1," according to CIESIN, is "a future world of very rapid economic growth....in this world people pursue personal wealth rather than environmental quality," as though it's always one or the other. CIESIN and the IPCC apparently do not understand that there is a strong and logical correlation between personal wealth and environmental quality. After all, excess capital is required for investment in increasingly clean infrastructure.

Curiously, these and other "storylines" were first published in a non–peer-reviewed report by Tom Wigley, a government climatologist at the U.S. National Center for Atmospheric Research. That report was produced by the Pew Foundation Center on Global Climatic Change, which itself has nakedly advocated the passage of the Kyoto Protocol on climate change. In his New York Times article, Andrew Revkin noted that the leaked copy of the IPCC document was supplied by "someone who was eager to have the findings disseminated before the meetings in the Hague" where the Kyoto Protocol is set to be implemented. Between now and the Hague lies Election Day.

When the Pew Foundation published Wigley's pamphlet, it issued a press release stating that his scenarios (the original "storylines") would be incorporated into IPCC's new assessment of climate change. Talk about an accurate forecast! What was then a non–peer-reviewed, illogical series of assumptions was apparently already slated to be the basis for the self-appointed "consensus of scientists" comprising the IPCC.

The 6°C warming hangs upon the slim thread of sulfate cooling, which is supposed to be dramatically cleansed from the atmosphere in the next few decades (resulting in enhanced warming). But, at the time the IPCC was finalizing its report, a paper appeared in the Sept. 15, 2000, issue of Geophysical Research Letters demonstrating that climate models using sulfate cooling and greenhouse warming simply cannot explain why integrated warming of the troposphere (the bottom layer of the atmosphere) is 10 times less than what was forecast for the last quarter-century.

To test of the sulfate hypothesis, consider Northern vs. Southern Hemisphere temperatures in the lower troposphere. As a landmark 1996 paper by Santer and colleagues shows, sulfate cooling in recent decades should have been more pronounced in the Northern Hemisphere, so that the difference between the two hemispheres (that is, Northern average temperature minus Southern) should be dropping significantly. In fact, this differential is, beyond a doubt, changing in a direction opposite what was predicted. As a result of this and other work, many atmospheric scientists, including the esteemed Gerry North of Texas A&M University, now believe that sulfate cooling has been drastically overestimated.

The high CIESIN/Wigley/Pew estimates not only assume that sulfates are important, but also that they will be rapidly removed from the atmosphere in coming decades, and are replaced by dramatically increasing greenhouse emissions. In fact, no one at all knows how our energy structure will evolve in the next 100 years. Consider the transitions of the last 100—from horses to jet planes, from wood heating to nuclear power, and a myriad of others—that were simply unpredictable. It is fair to say that what was not predicted to occur had a much greater impact on society that what was. And that's not anomalous: Try running a similar thought experiment between 1800 and 1900, and you'll net similar results. Yet the IPCC confidently assumes it can anticipate the next 100 years of technological change.

The same draft version of the IPCC report contains a summary of the dozens of computer models for climate change that do not use the silly CEISIN storylines (Figure 2). Instead, they use a (probably overestimated) exponential increase in greenhouse gases, and still the central tendency of all the models is around 2°C of warming for this century, or very near the bottom limit of warming (1.5°C) given by the IPCC.

Figure 2. The suite of IPCC models used in the upcoming assessment shows that their central tendency is a warming of only 2.0°C, or one-third of the value the IPCC report someone leaked to the New York Times.

The Times cites a broad consensus of scientists who believe human warming has been going on for some time now. And those scientists are very likely right, given the propensity for recent warming to be in the frigid air of winter—which is where IPCC-sanctioned greenhouse theory predicts the largest changes. But the IPCC climate models also average out to a straight-line warming, that, once it starts (at the surface it has been going on for decades), continues at a constant rate. If that's the case, and if the warming of recent decades is largely a human product, then we know the rate of warming for this century, barring any major decreases in greenhouse emissions. And that works out to right below 1.5°C.

What's more, the IPCC-predicted winter–summer differentials between models also remain quite constant, which means that this century is likely to experience a considerable warming of the coldest winter temperatures and relatively little change in the summer.

On the other hand, to reach the inflammatory and alarming projections described in the document someone leaked to the Times, we have to assume 1) illogical social behavior, 2) an ability to see the technology of the next 100 years better than anyone in human history, and 3) a notion of sulfate cooling that does not stand the test of reality, all from a text whose scientific conclusions were changed by government readers after the normal scientific review process had ended.

References:

Michaels, P.J., and P.C. Knappenberger, 2000. Natural signals in the MSU lower tropospheric temperature record. Geophysical Research Letters, 27, 2905–2908.

Michaels, P.J., et al., 2000. Observed warming in cold anticyclones. Climate Research, 14, 1–6.