http://www.realclimate.org
13 Dec 2004 Michael Crichton's State of Confusion
In a departure from normal practice on this site, this post is a commentary on a piece of out-and-out fiction (unlike most of the other posts which deal with a more subtle kind). Michael Crichton's new novel "State of Fear" is about a self-important NGO hyping the science of the global warming to further the ends of evil eco-terrorists. The inevitable conclusion of the book is that global warming is a non-problem. A lesson for our times maybe? Unfortunately, I think not.
Like the recent movie "The Day After Tomorrow", the novel addresses real scientific issues and controversies, but is similarly selective (and occasionally mistaken) about the basic science. I will discuss a selection of the global warming-related issues that are raised in between the car chases, shoot-outs, cannibalistic rites and assorted derring-do. The champion of Crichton's scientific view is a MIT academic-turned-undercover operative who clearly runs intellectual rings around other characters. The issues are raised as conversations and Q and A sessions between him (and other 'good guys') and two characters; an actor (not a very clever chap) and a lawyer (a previously duped innocent), neither of whom know much about the science.
So for actors and lawyers everywhere, I will try and help out.
The issues Crichton raises are familiar to those of us in the field, and come up often in discussions. Some are real and well appreciated while some are red herrings and are used to confuse rather than enlighten.
The first set of comments relate to the attribution of the recent warming trend to increasing CO2. One character suggests that "if CO2 didn't cause the global cooling between 1940 and 1970, how can you be sure it is responsible for the recent warming?" (paraphrased from p86) . Northern Hemisphere mean temperatures do appear to have cooled over that period, and that contrasts with a continuing increase in CO2, which if all else had been equal, should have led to warming. But were all things equal? Actually no. In the real world, there is both internal variability and other factors that affect climate (i.e. other than CO2). Some of those other forcings (sulphate and nitrate aerosols, land use changes, solar irradiance, volcanic aerosols, for instance) can cause cooling. Matching up the real world with what we might expect to have happened depends on including ALL of the forcings (as best as we can). Even then any discrepancy might be due to internal variability (related principally to the ocean on multi-decadal time scales). Our current 'best guess' is that the global mean changes in temperature (including the 1940-1970 cooling) are actually quite closely related to the forcings. Regional patterns of change appear to be linked more closely to internal variability (particularly the 1930's warming in the North Atlantic). However, in no case has anyone managed to show that the recent warming can be matched without the increases in CO2 (and other GHGs like CH4).
Secondly, through the copious use of station weather data, a number of single station records with long term cooling trends are shown. In particular, the characters visit Punta Arenas (at the tip of South America), where (very pleasingly to my host institution) they have the GISTEMP station record posted on the wall which shows a long-term cooling trend (although slight warming since the 1970's). "There's your global warming" one of the good guys declares. I have to disagree. Global warming is defined by the global mean surface temperature. It does not imply that the whole globe is warming uniformly (which of course it isn't). (But that doesn't stop one character later on (p381) declaring that "..it's effect is presumably the same everywhere in the world. That's why it's called global warming"). Had the characters visited the nearby station of Santa Barbara Aeropuerto, the poster on the wall would have shown a positive trend. Would that have been proof of global warming? No. Only by amalgamating all of the records we have (after correcting for known problems, such as discussed below) can we have an idea what the regional, hemispheric or global means are doing. That is what is meant by global warming.
full: http://www.realclimate.org/index.php?p=74#more-74
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