Friday, October 26, 2007

35 Inconvenient Truths, Continued.....

Pacific islands "drowning"

Gore says low-lying inhabited Pacific coral atolls are already being inundated because of anthropogenic global warming, leading to the evacuation of several island populations to New Zealand. However, the atolls are not being inundated, except where dynamiting of reefs or over-extraction of fresh water by local populations has caused damage. Furthermore, corals can grow at ten times the predicted rate of increase in sea level. It is not by some accident or coincidence that so many atolls reach just a few feet above the ocean surface.

Ms. Kreider says, “The IPCC estimates that 150 million environmental refugees could exist by the year 2050, due mainly to the effects of coastal flooding, shoreline erosion and agricultural disruption.” However, the IPCC cannot be basing its estimate on sea-level rise, since even its maximum projected rise of just 30 cm (1 ft) by 2050 would not cause significant coastal flooding or shoreline erosion. There are several coastlines (the east coast of England, for instance) where the land is sinking as a consequence of post-ice-age isostatic recovery, or where (as in Bangladesh) tectonic subduction is similarly causing the land to sink. But such natural causes owe nothing to sea-level rise.There have been no mass evacuations of populations of islanders as suggested by Gore, though some residents of Tuvalu have asked to be moved to New Zealand, even though the tide-gauges maintained until recently by the National Tidal Facility of Australia show a mean annual sea-level rise over the past half-century equivalent to the thickness of a human hair.

The problem with the Carteret Islands, mentioned by Ms. Kreider, arose not because of rising sea levels but because of imprudent dynamiting of the reefs by local fishermen. In the Maldives, a detailed recent study showed that sea levels were unchanged today compared with 1250 years ago, though they have been higher in much of the intervening period, and have very seldom been lower. A well-established tree very close to the Maldivian shoreline and only inches above sea level was recently uprooted by Australian environmentalists anxious to destroy this visible proof that sea level cannot have risen very far.

Thermohaline circulation "stopping"
Gore says “global warming” may shut down the thermohaline circulation in the oceans, which he calls the “ocean conveyor,” plunging Europe into an ice age. It will not. A paper published in 2006 says: “Analyses of ocean observations and model simulations suggest that changes in the thermohaline circulation during the last century are likely the result of natural multidecadal climate variability. Indications of a sustained thermohaline circulation weakening are not seen during the last few decades. Instead, a strengthening since the 1980s is observed.”Ms. Kreider, for Mr. Gore, says that “multiple scientists” have claimed that we cannot exclude the possibility of the disruption or shutdown of the Conveyor. Disruption, perhaps: shutdown, no. It is now near-universally accepted that the thermohaline circulation cannot be and will not be shut down by “global warming,” and the film should have been corrected to reflect the consensus.

CO2 "driving temperature"
Gore says that in each of the last four interglacial warm periods it was changes in carbon dioxide concentration that caused changes in temperature. It was the other way about. Changes in temperature preceded changes in CO2 concentration by between 800 and 2800 years, as scientific papers including the paper on which Gore’s film had relied had made clear. Ms. Kreider says it is true that “greenhouse gas levels and temperature changes in the ice signals have a complicated relationship but they do fit.” This does not address Gore’s error at all.

The judge found that Gore had very clearly implied that it was changes in carbon dioxide concentration that had led to changes in temperature in the palaeoclimate, when the scientific literature is unanimous (save only for a single paper by James Hansen, whom Gore trusts) to the effect that the relationship was in fact the other way about, with a carbon dioxide feedback contributing only a comparatively insignificant further increase to temperature after the temperature change had itself initiated a change in carbon dioxide concentration. The significance of this error was explained during the court proceedings, and was accepted by the judge.

Gore says that the 100 ppmv difference between carbon dioxide concentrations during ice-age temperature minima and interglacial temperature maxima represents “the difference between a nice day and a mile of ice above your head.” This would imply a CO2 effect on temperature about 10 times greater than that regarded as plausible by the consensus of mainstream scientific opinion (see Error 10).Ms. Kreider refers readers to a “more complete description” available at a website maintained by, among others, two of the three authors of the now-discredited “hockey stick” graph that falsely attempted to abolish the Mediaeval Warm Period. The National Academy of Sciences in the US had found that graph to have “a validation skill not significantly different from zero” – i.e., the graph was useless.

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