CCSP Draft Report Comments as Submitted by Professor Ben Herman of the University of Arizona

Comments on the CCSP Report “Unified Synthesis Product Global Climate Change in the United States by Professor Ben Herman

The following are the comments I sent in concerning the recent CCSP draft report. I chose a few issues of the many that I considered required a response, but felt that others would pick up them.

1. Background Information
Name: Benjamin Herman
Organization: University of Arizona
Mailing Address: Department of Atmospheric Sciences
Tucson Az 85721
Area of Expertise: Atmospheric Radiation and Radiation Transfer
Remote Sensing

2a. General Overall Comment

After reading through this report, I was quite disappointed at the overly biased results and interpretations of various issues as presented within the report. Many issues which, at present, are still not resolved, have been presented as though the conclusions within the report are without debate, and have been accepted by the community at large. As a result, the Societal Impacts, etc., have been presented as though all of the climatic issues are settled, and all that remains is to decide how to best proceed to minimize the impacts. In the following comments, I will point out a few of the issues with which I am most familiar. I am confident that others will comment on the numerous other points of importance.

2b. Chapter “Exec. Summary”, Page 11.

Climatic changes by region are presented. However,it is generally agreed by modelers that climate models cannot predict regional climate, nor were they intended to do so. This link presents references to a statement by Dr. Trenberth to this effect.

Regional climate change has been a subject of considerable research effort in recent years. Some semblance of the uncertainty that exists in this area of research should be included in the discussions.

2. Chapter “Global Climate Change”, Page 24, and Chapter “Exec. Summary” Page 6. The decline in Arctic sea ice is discussed and this certainly has occurred. But the recent rapid decline during the summer of 2007 is attributed only to melting in the report, but numerous studies have concluded that changes in oceanic circulation in the Arctic ocean have been at least partially responsible for this ice loss. In fact, it should have been obvious that such a sudden and large loss of permanent ice so close to the pole could not have been entirely a result of melting.

3. Chapter “Global Climate Change”, Figure, Page 17

Discussion does not mention the lag between historical rises in temperature and increases in CO2 and gives the impression that CO2 changes were the cause of the rises in temperature as determined from ice core data. This omission’ like many others, strongly slants the discussion towards CO2 induced warming.

4. Chapter “Global Climate Change”, graph, page 22

Indicates an increase in global temperature from about average (zero anomaly) in 1970 to about a 0.9 positive anomaly in 2005.This is a rise of about 0.9 degC in 35 years, or about 0.26 deg/decade, about twice the accepted rate of increase. Something is wrong here.

5. Chapter ” Global Climate Change”, paragraph below figure, Page 22

This discussion is about satellite data showing warming in the troposphere and cooling in the stratosphere, as models predict. Yes, the models do predict this, but they also predict greater warming in the upper troposphere then at the surface, particularly in tropical regions. Satellite data (MSU data) does not show this, it shows the troposphere warming at about the same rate as the surface. This has been a large topic of discussion during recent years and the disagreement is not mentioned in the report.

6. Chapter ” Global Climate Change”, first paragraph, Page 23

This implies an increase in Hurricane intensity and strength since the 1970’s. The link below has links to comments by Prof Kerry Emanuel in disagreement with these comments. Others have also disagreed with these comments, yet no mention at all is made of this.

7. Chapter “Global Climate Change”, Figure, Page 23

This figure shows the average summer tperature for 4 stations in Switzerland to demonstrate how much warmer the 2003 summer was than the other summers on record. Indeed, the 4 Swiss stations in 2003 were much warmer than all other summers. But, one must ask this question. What is the probability of finding a summer, where no region, anywhere in the world, experienced a heat wave with average temperatures about 2 degrees warmer than previously experienced in that region. In 2003, that region happened to be in Switzerland. Severe heat waves occur every summer, somewhere in the world. This occurance, by itself, is not an indication of Global warming and should not have been represented as such in this report. Why have the record cold and snow occurances in the southern hemisphere last winter not been mentioned?

8. Chapter ” Global Climate Change”, 2nd paragraph, Page 25.

An increase in westerly winds around Antarctica may very well have reduced the amount of warm, southerly flow into the water surrounding the continent, This is a reason given in the report for the record sea ice cover around Antarctica in 2007. However, is it not true that the same increase of westerly flow around the continent must also reduce the southward flow of cold air off of the continent, preventing freezing. This obviously did not occur. Therefore I think the explanation for the record sea ice is invalid.

9. Chapter “Global Climate Change”, bottom of page 26 and top of Page 27.

This discussion argues that stratospheric cooling and tropospheric warming must be due to the addition of greenhouse gases into the atmosphere, in agreement with models. Yes, that is true but the question remains as to how much warming is due to the addition of CO2 into the atmosphere, as well as other questions such as feedbacks, etc that are not adequately handled by the models. When a greenhouse gas is introduced into the atmosphere it must result in warming. There are many other variables and feedbacks which come into play here. Many other warming mechanisms, such as solar variations coupled with Ozone depletion can produce similar results. As has been pointed out in comment #5 above, the models do not properly predict the distribution of warming with height. This has been ignored in the report, but it is a basic feature of the model predictions, and it appears to be wrong. Therefore, it is certainly not correct to say that, since the models predicted stratospheric cooling and tropospheric warming, the models have it right.

10. In going over this report, I have found numerous other issues which are open to question, but I feel as I stated earlier, that others will comment on them. The ones outlined above are a few of the ones that I chose to comment on. I realize that the committee had a tremendous task to complete, one with so much research coming out monthly that it would be very difficult to include it all. However, I also feel that what was included was very biased towards convincing the reader that there is little question but that greenhouse gas effects are the primary cause of the recent warming, and there is little need to consider much else. I think this a dangerous direction to take in view of the many uncertainties that still exist in our overall understanding of the interactions of our atmosphere with radiation, chemistry, oceanic circulations (cause and effect), sources and sinks of these greenhouse gases, solar effects, surface land changes, etc.

We also have an incomplete knowledge of many feedback mechanisms, radiational properties and the effects of aerosols are not known accurately, will high level water vapor increase or decrease with warming, what will the effects of a prolonged decrease in solar activity be ( this was also not addressed in the report) as seems possible at this time. I have too many questions that I consider not known, or not understood well enough to draw such rigid conclusions as done in this report.


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