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useful.” 7 Climate models are no different. They don't capture individual clouds, and even when they
hypothetically could sometime in the future, they won't capture individual molecules, and so on ad
infiitum . Critics will always be able to point to something that climate models can't resolve. But
that's a red herring, the common fallacy that “because we don't know everything, we know nothing.”
As noted previously, climate models had already passed critical tests by the late 1980s and early
1990s, and since then they had become increasingly realistic in their ability to reproduce key features
of the climate system. Many of the climate models used in the AR4 assessment produced, for
example, very realistic-looking El Niño events. Enough credibility had been established to take the
models' basic predictions seriously: warming surface temperatures, more widespread continental
drought, vanishing Arctic sea ice, and rising sea levels given ever-increasing greenhouse gas
concentrations. Judgment: pillar crumbling if not yet toppled.
PILLAR 2
Consider now the second pillar of climate change denial that still remained in 2007: that the global
surface temperature record is ostensibly untrustworthy. 8 Traditionally, claims of contamination in the
surface temperature record have been based on arguments regarding the so-called urban heat island
bias —the observation that urban locations have typically warmed more than outlying rural areas
owing to different thermal characteristics of urban and rural environments (for example, asphalt
absorbs and retains more solar heating than a grassy field). To the extent that such locations are used
more frequently in constructing the temperature record, they could in principle lead to a warming
bias. Other types of changes in instrumentation and siting of meteorological stations—for example,
the placement of urban weather stations in artificially cool locations such as parks—could instead
lead to a cooling bias. Just how the potential warm and cold biases play out is not a priori obvious.
By 2007, though, a number of recent studies had assessed the extent to which any urban heat island
bias might still remain in the global temperature record.
A study in 2003 by NOAA scientist Tom Peterson and collaborators indicated that the cool park
effect largely mitigates any urban heat bias in the U.S. measurements. 9 A subsequent 2004 study by the
United Kingdom Meteorological Office's David Parker 10 tested for the presence of an urban heat
island effect by comparing temperatures on windy and calm nights across the globe, which should
show a difference if there is urban heat island effect, 11 and he found none. There were even more
basic reasons for rejecting the claim that the surface temperature record was compromised by urban
heat island effects. The global warming trend is seen not only in land measurements but also in ocean
surface temperatures, where obviously no urbanization is occurring. 12 The ocean warming isn't as
large as the observed land warming, but this is expected from basic physics and predicted by all
climate models, the primary reason being that heat efficiently diffuses down into the interior of the
oceans, leading to less warming at the surface. Judgment: pillar toppled.
PILLAR 3
What about the related third pillar: that other independent evidence contradicts surface evidence of
warming? The source of this claim was a set of analyses by one pair of scientists, John Christy and
 
 
 
 
 
 
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