Geoscience Reference
In-Depth Information
working in the NASA offices in Columbia University's Armstrong Hall
above Tom's Restaurant (made famous by the television series
Seinfeld
),
Hansen famously came to loggerheads with the George W. Bush adminis-
tration for its attempts to censor the results of climate science conducted at
NASA. In retrospect, the Bush administration could not have had a better
template for dealing with Hansen than the one Reagan's people provided
in 1981.
Silencing Hansen was the first in a series of ad hoc steps by the Rea-
gan administration to use the mechanisms of government bureaucracy to
quash the fruits of Carter-era research on CO
2
and climate change. The
effort included more than a reduction in research funding or the margin-
alization of individual scientists like Hansen; it also involved capitalizing
on professional and political divisions within the scientific community in
order to manage the public scientific message on CO
2
. The administration
used these tactics perhaps most effectively in handling a 1983 report on CO
2
produced by a National Academy of Sciences committee chaired by the
director of the Scripps Institution of Oceanography, William Nierenberg.
By 1980, the climate science community had come to agree on a few basic
principles vis-à-vis CO
2
and climate, but scientists from different disciplines
and institutions continued to disagree over the timing and magnitude of
a potential CO
2
-induced warming. In 1979, an NAS study chaired by Jule
Charney provided the first self-conscious scientific consensus on CO
2
and
warming.
62
The researchers concluded that a doubling of CO
2
would lead to
a 1.5- 4ºC increase in the global mean temperature— a warming that might
have significant social and environmental impacts.
63
As scientific debate
over Hansen's 1981 paper showed, however, unanswered questions about
the behavior of the oceans and the biosphere within the overall climate
system made it difficult to predict how quickly and how severely the real-
world climate might change in response to CO
2
. Though both the Charney
Report and Hansen's paper identified a moderate recent increase in tem-
perature associated with CO
2
buildup, the models revealed only the faintest
signal of a climatic response to the nearly 15 percent increase in CO
2
that
had occurred since the mid-nineteenth century.
64
Hansen argued that the
earth would begin to feel the impacts of global warming early in the twenty-
first century, but other scientists contended that the ocean-induced lag in
CO
2
's influence on the climate system could last a century or more, and still
others all but discounted the lag altogether.
65
