Singer letter to SciAm

By | July 24, 2007

According to the authoritative CCSP (Climate Change Science Program) Report 1.1, issued by NOAA in April 2006, there is considerable disparity between the two warming trends. Greenhouse (GH) models indicate that the tropics should provide the most sensitive location for validation; trends there should increase by 200-300% with altitude, peaking at around 10 kilometers – a characteristic “fingerprint” for GH warming. However, the data from weather balloons (and satellites) show the opposite result – no increasing trend with altitude but a lower trend than at the surface. The fingerprints just don’t match. Fig. 5.4G of the CCSP report ( makes this disparity quite clear; it shows the difference between surface and troposphere trends for a collection of some 20 models (displayed as a histogram) and for balloon and satellite data: This difference is positive for the data, but negative for the models. [The disparity is less apparent in the Summary, which displays model results in terms of “range” rather than as histograms.]

This is a crucial result, a “smoking gun” that contradicts the IPCC conclusion. Of course, it does not deny the existence of an enhanced GH effect from the considerable increase in anthropogenic GH gases, principally CO2. It does suggest, however, that present climate models greatly overestimate the magnitude of the effect. One may conclude, therefore, that future warming calculated from these same models will be a good deal less than currently assumed. Since there is little doubt about the radiative forcing from CO2 increases, one suspects that the models omit a negative feedback, likely from a slight increase in cloudiness or from a change in the atmospheric distribution of water vapor, the most important GH gas.


S. Fred Singer is professor emeritus of environmental sciences at the University of Virginia, and president of the Science and Environmental Policy Project. He did his undergraduate studies at Ohio State University and earned his Ph.D. in physics from Princeton University. He was the founding dean of the School of Environmental and Planetary Sciences at the University of Miami, the founding director of the U.S. National Weather Satellite Service, and served for five years as vice chairman of the U.S. National Advisory Committee on Oceans and Atmosphere. Dr. Singer has written or edited over a dozen books and monographs, including, most recently, Unstoppable Global Warming: Every 1,500 Years, which discusses the evidence for natural climate cycles of cooling and warming, as seen in the geological record.