Page 242 - James Rodger Fleming - Fixing the sky

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tHe Climate enGineerS

How can you engineer a system whose behavior you don’t understand?

—Ron Prinn, quoted in Morton, “Climate Change”

uring the unusually hot summer of 1988, with a major heat wave in
the American Midwest, Yellowstone National Park in flames, and
D issues such as ozone depletion in the headlines, climate modeler
James Hansen of NASA announced to the world that “global warming has
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begun.” Hansen reported that he was “99 percent certain that the warming
trend was not a natural variation but was caused by a buildup of carbon dioxide
and other artificial gases in the atmosphere” and that anthropogenic greenhouse
warming “is already happening now.” He predicted more-frequent episodes of
very high temperatures and drought in the next decade and beyond. Hansen
later revised his remarks, but his statement remains the starting point for recent
widespread concern about global warming. The question was no longer whether
human agency had contributed to global change. That question was answered in
the affirmative long ago. The more significant questions involved the magnitude
and consequences of the global changes being caused by a combination of natu-
ral forces and increasing anthropogenic stresses and what was to be done about it.
That summer, the government of Canada, in collaboration with the United
Nations Environment Program (UNEP) and the World Meteorological