Giant Brains - Four Revolutions in the Earth Sciences - page 227

By 1975, the GFDL model had become fully three-dimensional, with a “wet”
region to simulate the effect of the ocean on climate. It took into account changes
in snow cover and soil moisture but held cloudiness constant and still did not con-
sider heat transport by the oceans. The model projected a slightly higher temperat-
ure rise for doubled CO 2 than the 1967 version: 2.9°C. 6
In 1896, Arrhenius's pencil-and-paper calculations had shown “that the temper-
ature in the arctic regions would rise about 8 to 9°C, if the carbonic acid [CO 2 ]
increased to 2.5 or 3 times its present value.” 7 Manabe and Wetherald confirmed
that rising CO 2 would have its greatest effect in the Arctic, as a receding snow
line exposed dark, heat-absorbing soil to the rays of the Sun, causing more warm-
ing, causing more snow to melt, and so on in another amplifying feedback. Global
warming would cause the Arctic to warm significantly more than the globe as a
whole, offering another prediction by which to test global warming theory and cli-
mate modeling.
The 1975 model also showed that as the Earth warmed, evaporation would in-
crease and inject more water vapor into the atmosphere, where it would “signific-
antly increase the intensity of the hydrologic cycle of the model.” 8 In other words,
the model predicted more extreme weather events. Note that in this statement and
even in the title of their article, Manabe and Wetherald went out of their way to
draw a distinction between the results of their model and what might be found in
reality. Expressing a similar caution to that of Hulburt, the two said that the main
benefit of their results was to point out areas for improvement: “Because of the
various simplifications of the model . . . it is not advisable to take too seriously the
quantitative aspect of the results. It is hoped that this study identifies the require-
ments that have to be satisfied for the study of climate sensitivity using a general
circulation model.” 9
Global warming deniers repeatedly accuse climate scientists of exaggerating,
but from the outset they have been much more likely to understate their results.
One pioneering climate modeler who remains active today is Warren Washing-
ton (b. 1936). 10 Soon after receiving his Ph.D. in meteorology from Penn State
in 1963, Washington joined the National Center for Atmospheric Research, or
NCAR. The first model from the NCAR team used the computer of the UCLA
Medical School, requiring Washington to sit up all night tending to it. His team
displayed their results on a cathode ray tube, which they filmed with a camera.
One of their first successes was to produce a monsoon pattern of sinking air over
a simulated continent and rising air over a simulated ocean. For the model to settle
down to equilibrium took forty days—and forty nights. The NCAR modelers con-
firmedwhatthepioneersoftheCO 2 theoryhadknownbutbeenunabletotakeinto