The U.S. National Academy of Sciences
Issues a Distorted Report

(with additional responses by Prof Patrick Michaels and John Daly)

Comments on the National Academy Report on Climate Change
by  Prof S. Fred Singer

The panel was made up of 11 persons, some of whom were involved in the IPCC report. While well qualified individually, the panel lacked balance.  It did not include a geologist or glaciologist; nor did it include more than one identified skeptic or anyone critical of the IPCC report.  The panel also 
lacked demonstrated expertise in statistics, someone qualified to judge the adequacy of the data as a basis for conclusions drawn from them.  My comments are confined to the report's Summary (NAS/S), consisting of the first five pages of a total of 24.

Overall comments:

The very first sentence of the Summary (NAS/S) states unambiguously:

"Greenhouse gases are accumulating in Earth's atmosphere as a result of human activities, causing surface air temperatures and subsurface ocean temperatures to rise."

Only near the end of the report (p. 17) do we learn of the considerable uncertainties that could offset the clear and unequivocal conclusion of the first paragraph.

"Because of the large and still uncertain level of natural variability inherent in the climate record and the uncertainties in the time histories of the various forcing agents (and particularly aerosols), a causal linkage between the build-up of greenhouse gases in the atmosphere and the observed 
climate changes during the 20th century cannot be unequivocally established. The fact that the magnitude of the observed warming is large in comparison to natural variability as simulated in climate models is suggestive of such a linkage, but it does not constitute proof of one because the model simulations could be deficient in natural variability on the decadal to century time scale."

And they certainly could be!

In any case, the statement is wrong in several respects:

1. The claimed temperature rise of the past few decades is based entirely on surface data from poorly controlled stations and sea-surface measurements (of water not air temperatures); they are judged to be contaminated and therefore suspect. The NAS/S ignores the observed climate 
cooling that took place between 1940 and 1975, so obviously at variance with the increase in GH gases. It completely ignores the data from weather satellites and radiosondes, which show no appreciable warming trend since 1979. In addition, none of the many proxy measurement (tree rings, ice cores, etc) shows any warming trend after 1940.

2. Even if one were to accept the claim that the climate has warmed in the last 50 years, there is no evidence (in the form of "fingerprints," for example) that such a warming is human-related. On the contrary, the available evidence directly contradicts the idea that humans have made and are making a substantial contribution to temperature changes. Past century's trends can best be explained in terms of natural variability, most likely caused by solar variability.

3. Furthermore, if one were to assign such a warming entirely to an increase of GH gases, the "climate sensitivity" thus obtained would be well below even the lowest value quoted by the IPCC, a rise of 1.5C for a doubling of GH gases.

4. The observed warming trend of the deep ocean is best explained as a delayed consequence of the pre-1940 warming. There is also an observed cooling trend of the ocean, ignored in the NAS/S, again a reflection of a previous surface cooling (Singer in Eos, AGU Spring mtng 2000)

5. The first paragraph of the NAS/S mentions "associated sea-level rise" as if SL rise were a necessary consequence of an anthropogenic climate warming. Geologic evidence confirms that SL rise has been ongoing for the past 18,000 years and has resulted in a total rise of 120 meters [400 
. The current SL rise is mostly due to the slow melting of Antarctic ice sheets, which will continue for several more millennia.

Detailed comments:

a) NAS/S understates natural variability of climate by at least a factor of 100. The geologic record shows variability of a few degrees C in decades not millennia.

b) The "removal time" (lifetime) of CO2 as greater than 100 yrs is overstated by a large factor.

c) Notice how the NAS/S sidesteps the fact the atmosphere has not been warming since 1979 (according to satellite data): "The troposphere warmed much more during the 1970's than during the two subsequent decades." Of course; there was a major sudden warming between 1975 and 1978, unconnected to any human activity.

d) The NAS/S constantly refers to "observed warming of the last 50 years" in spite of overwhelming evidence against.

e) The NAS/S gives credence to extreme scenarios used by the IPCC and leaves the impression that a future warming of 5.8C is as likely as a lower value. But it admits later that the IPCC scenarios have already been proven wrong by actual observations of CO2 growth rates.

f) The very strange statement that "The contribution of feedbacks to the climate change depends upon climate sensitivity" should of course be reversed.

g) In discussing weather extremes on a regional basis, the NAS/S states "Some models project an increased tendency towards drought," but fails to mention that other models predict the opposite -- extreme precipitation for the same regions!

h) Finally, the NAS/S manages to sidestep the fact that the IPCC Summary, a political document, quotes the IPCC report selectively and exaggerates disasters while downplaying uncertainties. As the NAS/S puts it artfully: "The [IPCC] Summary for Policymakers reflects less emphasis on 
communicating the basis for uncertainty and a stronger emphasis on areas of major concern This change in emphasis appears to be the result of a summary process in which scientists work with policymakers on the document."
Yes indeed!


The Academy report stands or falls principally on whether the climate warmed in the past 50 years, and esp. since 1980. The overwhelming bulk of data from different independent sources shows no such warming trend. We are not talking just about science but about evidence. A full-scale open debate is in order to settle this matter.

2. Letter to Editor, New York Times (sent June 7)

The conclusion of the National Academy report to the White House that human activities are causing global warming [Front-page story in NY Times, 7 June] is largely based on the claim that there was an unusually rapid rise in surface temperatures during the last two decades, according to readings 
from surface thermometers. But another committee of the National Academy, with some of the same experts, published a report in January 2000 that tried to explain why the global atmosphere showed little if any warming since 1979, according to the best data from weather satellites and weather 
balloons. The current report makes no explicit mention of the incontrovertible disparity between the different data sets. Yet the obvious importance of this matter for setting national policy calls for an 
evidentiary hearing in an open, trial-like setting during which the proponents of the differing data sets can be questioned and cross-examined in front of a jury of scientists and non-scientists.

S. Fred Singer
Professor emeritus of Environmental Sciences
University of Virginia

3. Postscript: National Academy Report On Global Warming
(Prof Patrick J. Michaels)

Two weeks ago I saw the list of participants who were asked by the White House to produce a new report on global warming via the National Academy of Sciences. Two weeks ago, I knew what the report would say: that, while uncertainties remain, global warming is an important problem and that the planet will warm somewhere between 1.4 and 5.8C by the end of this century.

This is the same range projected by the United Nations' Intergovernmental Panel on Climate Change, in a report to be released with great fanfare some sixty days from now. The reason that the National Academy report looks a lot like the UN's is that it was produced by a microcosm of the same people, and with the same process: groupthink.

In order to produce whatever you want, all you have to do is select the right people. But, for cover, include one or two known dissenters who can then be listed as participants even as they are ignored by the dynamics of the larger group.

I know because I have been in similar meetings with many of the very same people on the Academy panel; instead of being called by the White House, the one I recall was requested in response to Congressman John Dingell (D-MI). Eric Barron, from Penn State, a member of the current Academy 
panel, chaired the meeting. There were about 15 participants, the same number involved in this most recent report. And what "we" said then looks quite a lot like what the Academy said yesterday.

The other dissenter in that case was MIT's Richard Lindzen. For several hours, we raised a number of objections concerning facts and uncertainties about climate change. Finally the Chairman announced that if we didn't stop objecting he was going to stop the meeting. This is how legitimate 
scientific dissent was handled.

We can only surmise that similar things happened with the new report by looking not at what it says, but what it omits. In this case, the two likely dissenters were again Mr. Lindzen, and John ("Mike") Wallace, who chairs the Atmospheric Science Department at University of Washington. Wallace invited me for a very well-received seminar last year and expressed considerable agreement with arguments that warming may well be overestimated, and that the process by which we assemble "consensus" (the new report being the latest example) may be fundamentally biased. But he also thinks we should lower our use of fossil fuels, his personal opinion.

Want proof that groupthink smothered inconvenient dissent in this new report? Here are four glaring examples:

1. Lindzen recently published a bombshell paper in the Bulletin of the American Meteorological Society demonstrating there is a huge tropical "thermostat" that regulates planetary warming. It reduces the likely warming in the next century to, at warmest, somewhere around 1.6C, or the 
lowest end of the National Academy's range. I find no mention of this paper in the new Academy report. It is impossible for me to believe that Dick did not bring it up.

2. The first sentence of the Academy report talks about how changes in the earth's greenhouse effect are "causing surface air temperatures and subsurface ocean temperatures to rise". Wouldn't it be logical if one then immediately asked what this meant? The paper on ocean temperatures was 
published only three months ago, in Science. When the rise in ocean temperatures is coupled to a predictive climate model, the warming for the next 100 years again comes out at the low end, around 1.4C.

3. Almost all of our climate models predict that once human warming starts, it takes place at a constant (not increasing) rate. The Academy report concurs with the UN that much of the warming of the last several decades is caused by people. Therefore, the warming rate that has been established 
should be the most likely one for the next 100 years, unless all those climate models are wrong. Again, it works out to 1.4C.

4. The physics of the greenhouse effect requires that warming begin to damp off if the increase in a greenhouse compound is constant. So the only way that the computer models can maintain a constant warming rate for the next 100 years is to assume that the greenhouse gases go in at ever-increasing (exponential) rates. They are not doing this. Despite the prior beliefs of every atmospheric scientist on the Academy panel, the increase in the last 25 years has been constant, not exponential. This will tend to reduce, rather than maintain warming in coming decades. The Academy report makes brief mention that the increase in atmospheric greenhouse gases is below the projections of the UN, but that's all. If one assumes their projected range, a non-exponential increase in greenhouse gases will drive the warming right down to it's bottom, or 1.4C in this century.

Is there a pattern here? You bet. By far the most consistent interpretation of that thing that climatologists must ultimately confront -- reality -- is that warming is destined to be modest. Further, the atmosphere has already told us that two-thirds of this will take place in the winter, with three quarters of that in the dead of Siberia, north-western Canada, and Alaska.

The logical question to ask is why the Academy didn't put all of these things together, and instead left it to this predictable nag to do it for you. The answer is simple: the people on this panel are largely the same ones who produce the United Nations reports, as well as earlier Academy reports. They have been touting big warming for nearly two decades. Reversing course, and saying anything else would have been self-destructive. That's why the contents of this report were quite predictable, with as small a range of uncertainty as is indicated by a critical look at our climate's behavior.

4. A view from Australia:
John Daly's Critique Of The NAS Report

(adapted from

This report contains no new science, no new evidence, and most critically - it did not address in any detail a single point of contention raised by global warming sceptics. Specific problems with this latest report are:

"Temperatures are in fact rising" - Only according to the surface record, mostly from third world instruments. The satellite record shows little or no warming, and the surface record from the U.S. shows a climate today little different to what it was 70 years ago. This remark confirmed the 
committee's support for the surface record - no reason given.

"There is general agreement that the observed warming is real and particularly strong within the past twenty years." With this remark, the committee have clearly rejected the satellite temperature record outright, with not a single reason offered. Because the satellites show no strong warming `within the past twenty years', the committee clearly have given 100% blessing to the disputed surface record - without so much as a reason to justify that choice.

"The committee generally agrees with the assessment of human-caused climate change presented in the IPCC Working Group I (WG1) scientific report." - So they toss the ball back into the IPCC court, choosing not to raise a single point of criticism of that over-politicised UN body. This is hardly 
surprising as several committee members were themselves involved in the IPCC process.

"The committee finds that the full IPCC Working Group I (WG 1) report is an admirable summary of research activities in climate science, and the full report is adequately summarized in the Technical Summary." The IPCC summary was also highly selective, choosing to summarise only those research activities which reinforced the IPCC mindset. That this NAS committee should find it so admirable clearly establishes them as ideologically pro-IPCC with no scientific justification offered. They gave no reasons for the selectivity exercised by IPCC reviewers, accepting some research 
studies, but ignoring others.

"After analysis, the committee finds that the conclusions presented in the SPM and the Technical Summary (TS) are consistent with the main body of the report." - Again no discussion of the numerous points of difference between the two IPCC documents raised many times by sceptics. The SPM and TS are clearly incompatible in many respects, but the committee again resorts to 
endorsement without justification.

On sulfate aerosols, whose effects are highly disputed - "The monitoring of aerosol properties has not been adequate to yield accurate knowledge of the aerosol climate influence." This is an admission that little is known about these aerosols, but the committee did not proceed to find any fault with models which use those aerosols to prevent the models from over-heating their virtual earths beyond existing real climate. Those aerosols are used in the models like an accountant's `balancing item' in a balance sheet, and are assumed to be real only in order to keep the models in some kind of agreement with current climate. The committee should have been more detailed on this issue, given their admission that little is known about the effect of aerosols in the real world.

On solar forcing, the direct effect of which the committee claims to be small (+0.3 w/m2), they dismiss the well published secondary feedback effects of solar forcing - "Numerous possible indirect forcings associated with solar variability have been suggested. However, only one of these, ozone changes induced by solar UV irradiance variations, has convincing observational support."  With these dismissive words, the entire body of published and peer-reviewed solar science built up over the last ten years is thrown out - without so much as an explanation.

On the `National Assessment' - "The U.S. National Assessment of Climate Change Impacts, augmented by a recent NRC report on climate and health, provides a basis for summarizing the potential consequences of climate change."  The National Assessment has been one of the most criticised climate documents of recent times. It was attacked not merely by global warming sceptics, but also by scientists normally sympathetic to the IPCC and the global warming scenario. It was a manifestly political and alarmist document and exceeded even the alarmism normally associated with radical environmental groups. But this NAS committee endorses the National Assessment. More shame to them for doing so.

On the delicate issue as to why the satellites and surface do not agree as to recent warming trends - "The finding that surface and troposphere temperature trends have been different as observed over intervals as long as a decade or two is difficult to reconcile with our current understanding of the processes that control the vertical distribution of temperature in the atmosphere." With these mealy-mouthed words, the committee put themselves squarely in the business of pseudo-science, not science.  Having admitted they could not understand why the satellites measuring the free 
atmosphere were producing a different trend to the surface record, this lack of understanding did not compel them to question the validity of the models which depend critically on an assumption that an enhanced greenhouse must warm the troposphere first, before the surface warms. What has been observed is quite the reverse. From this, it requires no great leap of thinking to conclude that either the models are working to a completely false premise, or else the surface record itself is wrong, or both. Either way, having endorsed the models without explanation, and having endorsed the surface record again without explanation, they could only pass off this fundamental conflict with the inane and worthless comment given above.

In conclusion, the NAS committee made many assertions, none of which they chose to justify or explain other than to state it was `their view' - as if their mere authority as representing the National Academy of Science were enough to prevail in the argument.

Well it isn't. The days when mere `authority' could win an argument or debate are long gone. Such deference is more characteristic of a medieval priesthood, not a modern science where every important claim must be justified and explained. Only evidence counts in this modern world, and 
this committee have provided none, merely re-stated what has already been stated in politically contaminated documents by the IPCC and National Assessment.

S. Fred Singer May 22, 2001
Professor emeritus of Environmental Sciences
University of Virginia, USA

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