Michael Crichton’s State of Confusion

Another issue that often comes up in discussion about the surface temperature record is the impact of the Urban Heat Island Effect (UHIE), and here it appears on p370. It is undisputed that the centres of cities such as New York are significantly warmer than the surrounding countryside. This issue has been extensively studied and is corrected for in all analyses of the global temperature trends. To see whether there might still be a residual effect in the corrected data, a recent paper (Parker, Nature, 2004) looked at the differences in the trends if you looked separately at windy and not-so-windy conditions. Wind is known to diminish the impact of urban heating, and so the trends on windy days should be less than trends on still days if this was important. The trends actually end up almost exactly the same. Other validating data for the corrected surface temperature record comes from the oceans, which have also been warming in recent decades. Even Richard Lindzen , normally an arch-skeptic on these issues, stated that “ocean temperature increases present some support for the surface temperature record” Lindzen (2002). Another demonstration that the corrections are sufficient is that over the continental US, where many cities have a clear urban heating signal, the mean of the corrected data is actually rather flat (p88) – i.e. none of the strong urban biases in the US has made it into the regional or indeed global mean.

A central issue in the book concerns sea-level rise. Vanuatu is singled out for special attention since the islanders there are understandably concerned about their low-lying islands eventually being swamped. Sea level however is a surprisingly difficult thing to measure. Tide gauges are very noisy, and are usually located on the continental coast. Global trends in sea level from these gauges are between 1.7 to 2.4 mm/yr. Sea level though is not rising everywhere. In Scandinavia the continents are still rebounding from the ice age and local sea level is receding. Satellite data (TOPEX/POSEIDON and JASON) can give a global picture, and indicate that although the global mean rise over recent years (2.8 mm/yr) is significantly larger than the longer term trend estimated from tide gauges, sea level change is actually very dynamic. There are many patterns of behaviour particularly in the Pacific, associated with El Nino variability – possibly related to Vanuatu’s lack of actual sea level rise over the last 40 years. Curiously, Crichton cites the higher satellite derived number to claim that the rate of sea level rise has not increased recently (“[Sea level is] rising faster, Satellites prove it”,”Actually they don’t”), p424. There are clearly some problems in comparing tide gauge and satellite data, and of course, satellites can have their problems (cf. MSU data), but the quoted numbers don’t support the actual statement at all – though it would be fairer to say that the satellites are consistent with a recent rise in the rate, rather than a proof that it is occurring.

There are only a few out-and-out errors, but to be generous, they probably just slipped through the editing process. For instance, on p187 “higher temperature means more water vapor in the air and therefore fewer clouds” – Presumably, he meant that if the temperature is higher, the relatively humidity could be lower (and so there might be less clouds). On p368. “Croplands are warmer than forested lands”. This is probably a confusion with the urban heating issue, but the actual impact is the opposite – croplands have a higher albedo than forests, reflect more solar radiation, and are thus cooler. In fact, while this is not yet fully quantified, it appears to have been a significant cooling term in the global budget over the last 150 years. On p461 “…Greenland shows that, in the last hundred thousand years, there have been four abrupt climate change events” More like 40. And that is probably an undercount given that Greenland may not record events in the tropics.

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