Michael Crichton’s State of Confusion

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 Cruz 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.

Crichton next raises the apparently unrecognised (by the lawyer character at least) fact that the interior of Antarctica is cooling (p196), an issue discussed in another post (Antarctica cooling, global warming?). This is more or less correct (given the obvious uncertainties in long term data from the continental interior), but analogously to the example above, local cooling does not contradict global warming.

Next, and slightly more troubling, we have some rather misleading and selective recollection regarding Jim Hansen’s testimony to congress in 1988. “Dr. Hansen overestimated [global warming] by 300 percent” (p247). Hansen’s testimony did indeed lead to a big increase in awareness of global warming as a issue, but not because he exaggerated the problem by 300%. In a paper published soon after that testimony, Hansen et al, 1988 presented three model simulations for different scenarios for the growth in trace gases and other forcings (see figure). Scenario A had exponentially increasing CO2, Scenario B had a more modest Business-as-usual assumption, and Scenario C had no further increases in CO2 after the year 2000. Both scenarios B and C assumed a large volcanic eruption in 1995. Rightly, the authors did not assume that they knew what path the carbon dioxide emissions would take, and so presented a spectrum of results. The scenario that ended up being closest to the real path of forcings growth was scenario B, with the difference that Mt. Pinatubo erupted in 1991, not 1995. The temperature change for the decade under this scenario was very close to the actual 0.11 C/decade observed (as can be seen in the figure). So given a good estimate of the forcings, the model did a reasonable job. In fact in his testimony, Hansen ONLY showed results from scenario B, and stated clearly that it was the most probable scenario. The ‘300 percent’ error claim comes from noted climate skeptic Patrick Michaels who in testimony in congress in 1998 deleted the bottom two curves in order to give the impression that the models were unreliable.

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