SPM-3, lines 18-19. "in recent decades" is misleading. It conveys the impression that the composite temperature indicator (Figure 3.3) is at its highest value; it clearly is not, and the highest values were reached in the 1930s with the big rise between the 19-teens and the 20s; look at the figure. For accuracy, the text should read, "Composite indicators of summer temperature indicate that a rapid rise occurred around 1920, and that made the 1920s and 1930s the warmest decades since at least around 1400. This rise was prior to the major greenhouse emissions. Since then, composite temperatures have dropped slightly on a decadal scale." Again, take a look at figure 3.3 carefully.

Lines 24-26. These are wrong. SOI values 1990-1995 are not distinguishable from 19101917, a slightly longer period. The statement about the behavior between 1990-95 must therefore be deleted; leaving it in will compromise the scientific credibility of the document because critics will point to the similarity between the two periods (in spite of the fact that the global temperature was lower and that the transition from 1917 to 1920--after the prolonged El Nino ended--was perhaps the most notable warming period in the entire instrumental record).

SPM 11-Lines 5-6. In order to protect credibility, it's always advisable to tell the whole truth. Therefore the statement "This estimate is smaller than that.." should be changed to, "This estimate is 50% less than that given...."

SPM-13, insert in line 24:

"Radiosonde, Microwave Sounding Unit (satellite), and surface-measured temperatures show no statistically significant change beginning in 1979. After adjustment for volcanism and El Nino, the satellite data continue to show no significant trend."

SPM-13, lines 34-35. See comment on SPM-3, lines 18-19, above. It is very important that you state this accurately or criticism may be very sharp.

SPM-14, lines 12-13. Same as SPM-3, lines 18-19.

Lines 39-40. The repeated citation of in the entire document, including the SPM, of "10,000 years" concerns me. Clearly, the addition of another 1,000 years brings us back to periglacial conditions, and therefore larger climate oscillations generally associated with a colder climate. Why just stop at 10,000? Because the ecological effects of natural climate change 11,000 years ago dwarfed anything humans can do??

SPM.15, lines 29-30. Most scientists would associate stronger extratropical cyclones with an increased temperature gradient; the opposite is predicted for an enhanced greenhouse effect. Add the statement, "This observation is not consistent with greenhouse projections that reduce the pole-to-equator temperature gradient. Further, there is no significant change in strong extratropical cyclone activity; intense tropical cyclone activity in the Atlantic has decreased significantly".

SPM-21, 38-40. Suggest you look at Michaels et al., (1994; Technology 331A, 123133). Sulfate aerosols are not a sufficient explanation for the known pattern mismatch between nonsulfate greenhouse GCMs and observations.

SPM 22, 38-39. Add, "There are also broad areas of considerable inconsistency between sulfate-greenhouse models and observations; these areas are the same regions where these models predict the largest warmings". This, of course, refers to the polar regions, especially in winter.

SPM 23, lines 5-13. This paragraph is wrong and will harm IPCC if it remains. MSU satellite data show no signal that is at all consistent with a sulfate modification of greenhouse warming. Critics will surely point this out as evidence for sloppy science if it remains in this Summary. Best leave the whole paragraph out rather than try to explain away the MSU with a bad argument.

Lines 14-15. Asking for trouble here. By citing the "natural variability" argument heavily in previous editions, and now switching to the absolute statement that "global-mean temperature changes of the last century are unlikely...." you're liable to be severely criticized. Best to modify the statement by saying "Some of the global-mean...."

SPM-26, lines 1-2. Previous reports said CO2 and non CO2 greenhouse contributions were roughly equivalent. You need to explain the change here (which will be very difficult).

SPM-29, lines 1-2. Chapter three notes that there is no evidence for an increase in extreme high temperatures while there is a decrease in the severity of extreme lows. You need to differentiate between these events here.

SPM-30, lines 30-31. This statement has been repeated so many times, it may ultimately be known as "Trenberth's Folly". See previous commentary. Leave it in as is and there will be sharp criticism.

SPM 34-35: Regional estimates. Delete. They are unreliable. IPCC should be aware that the unreliability of these selfsame predictions from previous editions has served as the basis for overturning or refusing externality costs for CO2 emissions in civil proceedings in several states in the USA. Leaving them in therefore harms environmental protection (if one believes that emission reductions are desirable, as does the head of IPCC).

TO: Mike MacCracken, U.S. Review Coordinator, IPCC 1995 Synthesis Report

FROM: Patrick J. Michaels, University of Virginia

2903

Following is my review of the 1995 Synthesis Report.

I again express my concern, as I have several times this year, that I was refused the most critical piece of data pertinent to a proper review of this document, which is the high latitude transient gridcells of the GHG and SUL models from UKMO. Any excuses about upcoming publications no longer apply, and, if in fact that were the case, these reviews are not a public matter anyway.

The fact that Mr. Houghton is the head of both UKMO and IPCC places IPCC in a very serious situation here.

Sincerely

Patrick J. Michaels
Virginia State Climatologist

Review of 1995 Synthesis Report

COMMENTS ON THE POLICYMAKERS SUMMARY

Draft team: The drafting team represents, in large part, only one part of the political spectrum on this issue. I see not one of the well-known "skeptics" or technological optimists.

Section 2.2. Last sentence is misleading and meaningless. Of course there are secular changes in regional climate variables. If there weren't there would be no need for weather forecasters. Strike the sentence; leave the previous one in.

Section 3.2. The given range is not right. According to figure 7, the range with aerosols is 0.8 to 2.4° In reality, it should be somewhat less than 0.8 because the lower limit in the aerosol and non aerosol models cannot logically be the same. Therefore the sentence should read"... global mean temperature of somewhat less than 0.8°C to 2.4°C by 2100." A further misread occurs in the non sulfate models, where the top should be 3.2°C and the lower limit 0.8. See figure 7.

The aerosol scenario gives a mean warming of 1.6°C, which represents the lowest mean ever projected by IPCC, and IPCC should emphasize this. An acknowledgement of the "cynics" that IPCC marginalized in 1990 (i.e. the folks who turned out to be right) wouldn't hurt here either.

At any rate, with the 1.6°C, you have to lower the sea level to a median of 0.35 m, or a range of 0.1 to 0.6.

How can you project increased floods and droughts--they're regional events?

4.3.a This is obviously an attempt to inject some ecological relevance into this disappearing problem. at 0.1°C/decade the microclimatic diversity is surely enough to create ersatz migration corridors. We don't live in a static society anymore, either.

4.3.c Note to Larry Kalkstein. If climate only determined disease, Northern Australia would be a Malarial miasma. Sanitation, not an impoverishing carbon tax on producer nations, prevents malaria. Carbon taxes help it by destroying the benificent economies.

4.7 Sounds like an assertion at an undergraduate bull session. Prove it or remove it.

5.5 and its ilk neglect the finding that the temperature forests of the midlatitudes can store 360 tg of carbon per year (if proper management continues). All statements on drawdown times have to be radically changed to reflect this finding. Keep them in like this at IPCCs peril. Wait till Sherwood Idso and Sylvan Wittwer get a hold of them.

6a Natural gas used to produce 70% of the carbon/btu of coal. Now its 58%. What changed? Better gas? Dirtier coal? New coal combustion (ceramic) technology will surely change this. Making this report a mandate to kill coal is not, repeat, not a very good idea.

6.9 What is a market pull? If you mean market distortion say it, 1984 has passed.

REVIEW OF OVERALL TEXT

2.6 This is a meaningless paragraph, attempting to inflame those who don't know better (i.e. "policymakers"). Discard.

2.7 Try adding this at the end. "However, any anthropogenerated signal is very small and so subtle that it would not have been noticed by anyone but extremely quantitatively oriented scientists."

3.4 The assumptions about CFCs are guaranteed to inflate forcing. Note that concentrations are already levelling off.

3.15 This is inconsistent with the policymakers summary. It should say (see my earlier text) less than .08°C/decade to .24°/decade with sulfates and....analogous figures without.

3.16 Adjust sea level re my earlier criticism of spm

3.19, 3.20. IPCC now acknowledges that GHG only models overpredict warming (and therefore everything else). Why are these sections here? Delete them or be careful of the upcoming criticism.

4.3. You've got to be kidding! Take North America: Annual temperature range of 90°C, highly mobile population. Does life expectancy decrease as one moves south? The problem here is not climate change, it's governments that place their people at risk through incompetent management.

4.4 The same argument as in 4.3 applies here, Mr. Kalkstein.

Box, page 12. Natural ecosystems are not necessarily more vulnerable. Diverse systems are more stable and create their own microclimates more effectively. A planted stand of Loblolly Pine doesn't have the either the genetic or the microclimatic diversity of the mixed. mesophytic forest.

4.5 See 4.3c from the Policymakers Summary. Try sanitation rather than carbon taxes. Which is more effective?

4.9 David Legates (J Climatology) demonstrated that the model forecasts of precipitation are childishly bad and vary dramatically between models. Leave statements like this in and