Statistics

New York Times debate on AGU statement

The American Geophysical Union, of which I am a member, has, like many other organizations, e.g. the ASA, issued a statement concurring with the IPCC report. The text of that statement is here.

So far, nothing unusual, except that this statement was noticed by the New York Times and written about here. But Marc Morano, a staffer to Senator Inhofe of the now infamous “Inhofe 400” posted a comment saying “this new AGU statement appears to in no way represent the views of the AGU rank-and-file members.”

Nobody can know whether or not that is true; that is, the entire rank and file are never polled. What happens, and I am on committees to write just these kind of statements, is that a small group writes a statement, which is put out for public comment. All comments must be answered, but, however, not all comments need be incorporated in the statement. After a period of time has passed, the statement is reworked and sent to some executive body which approves it. Most regular members do not notice these statements, nor do they take the time to be involved in their creation and editing. Most would not care, for example, about words changes one way or the other. And not all members would concur with the final wording the statement.

This the main point: just because an organization issues a report it does not follow that all who belong to the organization support that report. You would think any experience with any politics whatsoever would be proof enough of that. But, no. Andrew Revkin, who wrote the Times’ piece, offered to post, in bold, comments from AGU members who disagreed with the AGU statement. Quite a debate is unfolding at that site.

Here is the opening sentence of the AGU statement: “The Earth’s climate is now clearly out of balance and is warming.” And here is what I wrote:

I am a member of the AGU and the AMS and I do not support the language used in the AGU statement. Here is why.

I find the AGU statement, while accurate and useful in places, to be needlessly sensational and overconfident in others. To start the document with the statement that the Earth is “clearly out of balance” is silly and purposely provocative. It is a feeling among certain scientists that a little exaggeration in “the cause” is justified to “raise awareness”, but I disagree: it always does more harm than good. This statement will raise as many hackles as it does “awarenesses.”

There are some matters of observation and theory of which AGU members and scientists are competent to comment upon, but there are other topics in the statement that they are not, and I find the language used to express the certainty of these forecasts—and they are forecasts, for example, the “loss of biodiveristy” plug—to be far too strong. Or to say it another way, the statement is too sure of itself.

My last complaint will seem out of the blue, but I hope you will consider it: there is not one word about the possible benefits of warming. To say that there would be none or that they would be trivial is surely too strong.

Now, if you argue that no words of possible benefit should be in a statement like this, I would agree. But then I would also say that no words of possible harm should, either. Instead, the statement should be strictly limited to the science, couched in the language of probability: the warming will be this and such; a certain area will see X% more, another Y% less; there is a X% chance that if CO2 is reduced to a certain level, the warming will be reduced by Y%; and so on. Plain, simple, non-sensational, quantitative, verifiable predictions.

Obviously, there is much more to be said, particularly about the manic desire, most strongly felt in civilians, that it be true that mankind is causing warming. For example, here is the first comment to the Revkin story:

Right on! Andy. Yes! Yes! Yes! I?m sure I?ll be shaking my head in horror upon the first post that challenges ALL these institutions from SCIENCE AND SPACE but Jesus, what more do non believer?s, denialists need to get the point we need to act NOW? All of us!
This article is great!

There are others like that, equally breathless. Most of the running commentary is on peripheral questions, little of it answers comments made by people like me and Perry Clark (comment #3). Clearly, there is more to be said about the desire question, but I’ll have to pick that up later.

Categories: Statistics

5 replies »

  1. I completely agree with your comments. However, if the AMS statement adhered to your suggestions no one would read them or care.

    I have immersed myself in trying to learn more about the climate and in the months that I have studied it here are some of my impressions.

    1. The science of Climatology is unbelievably complex, and the discipline of radiation physics very poorly understood from a fundamental level. While in theory GHG likely could influences temperature in a positive manner no one can possibly say how or how much from first principles. All calculations to determine the temperature increase from GHG that I have seen have always assumed that all of the current current warming is caused by GHG. This seem unlikely. There appears to be better correllations with PDO/AO and Solar Activity than GHG. While this is proof of nothing, it should give any prudent scientist pause. Another pet peeve of mine is that the “cartoons” of radiative transfer are only for daytime. Surely the transfer mechanisms are very different at night and might they be negative? Also the paleo record indicates periods of orders of magnitude higher CO2 quantities in the atmosphere. Why didn’t the earth end then?

    2. The temperature data record is just a mess. Nineteenth and early 20th Century measurements surely give only ballpark temperatures.The GISS temperature data record is massaged in a manner unknown and unrevealed by it’s keepers. As revealed by the hockey stick debackle this is unacceptable. The satellite measurements are better, but as I understand them the instruments where not intended as temperature monitors and require a great deal of manipulation. Also the RSS and UAH give slightly (but statistically different?) results. The RSS temperatures have had to be recently adjusted (again a statistically significant amount?). These discrepancies in data make all sorts of data manipulation possible. ie which ones are used, date baselines, averaging, smoothing etc. This drives a layman like myself to absolute distraction.

    Scientists should always remain skeptical and especially so with the present Climate controversy. That organizations like the AMS issue advocacy statements like this is totally unacceptable. They should keep to rigorous science and thus in the background.

    Off topic. I saw on youtube Dr Bill (?)Carter (Australian) use a proxy graph for the rate of change of temperature in the Holocene. He drew two lines and stated that the average rate of change for the recent Holocene was 2.5 Deg C per century. This he said was a very strong indication that the changes we are seeing today are normal. I am intuitively uncomfortable with this statement, but cannot put my finger on why. I tried to find the raw data on this but cannot . I wanted to get the data to see if I could calculate the mean, or mode and see if one of those values would seem more likely. What are your thoughts on this. Is it a valid statement?

    By the way I love your site and enjoy your writing. I am a complete dummy when it comes to statistics, but that doesn’t make me appreciate you site any less!!

  2. “It is a feeling among certain scientists that a little exaggeration in ?the cause? is justified to ?raise awareness”………..”

    These people cannot properly be called scientists, they can only be called politicians or religious converts………..I sometimes give expert testimony in court and I suspect that the above attitude might land me in prison. At the very least it would (and should) destroy my credibility.

  3. To Steve Hempell
    I read through Carter’s original paper where he shows a plot of a the rate of temperature change over time (the derivative not the measurement itself). This graph shows that periods of rapid temperature change are not uncommon. The average of 2.5 degC/century sounds reasonable when you look at the graph.

    I was a bit skeptical as well so I loaded the GISP2 ice core data into excel and double checked Carter’s graph and did not find any discrepancies. The only criticism I have of his claim is one ice core does not a planet make.

    Carter’s paper is here: http://members.iinet.net.au/~glrmc/2007%2005-03%20AusIMM%20corrected.pdf

  4. Raven:

    Thanks very much.

    I agree with your criticism. There are other ice cores. I assume that this is a time consuming and not trivial task. Otherwise, I would assume other people would spend the time to do it to see if other ice cores confirmed such a result.

    If they did, wouldn’t this be a stake in the heart of the catastrophic aspect of the current climate change – the 20th century warming being less than 1/2 this amount? I don’t think even the last 30 years are at this average rate.

  5. All,

    I have just finished reading Carter’s “Myth” paper, and listening to his radio interview, and Youtube (http://youtube.com/watch?v=FOLkze-9GcI ) videos. I think all these are excellent resources and should be read and viewed by all.

    His work is excellent and, my highest compliment, statistically sound. In fact, I think I will link his Youtube talk on the main page so that others will find his work more easily.

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