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could be masked for timescales as long a decade or more by the impacts of natural variability. 21
While some scientists have disputed the magnitude of the effect, there is no debate within the
mainstream scientific community over the validity of that basic premise. However, the finding was
misrepresented by contrarians, and frequently misunderstood in popular accounts that presented the
work as if it called into question the reality of human-caused climate change, 22 even though the
authors were explicit that their study did nothing of the sort. 23
Reenergized “global warming has stopped” claimants seized upon the sort of cherry-picking that
would put even the very best fruit farmer to shame: An unusually strong El Niño event raised global
temperatures in 1998, making it the warmest year on record in one of the three global temperature
assessments, that of the University of East Anglia's Climatic Research Unit (CRU), while 2005 beat it
out for the record in the other two assessments. 24 Contrarians noted that if they used the CRU record
and chose the starting year as 1998, they could make the misleading argument that global warming had
stopped because temperatures were cooler in subsequent years. Calculating the trend over the
subsequent eight years, say, one could use the CRU record to seemingly argue against a net warming
trend. This tells us nothing about global warming, however. It is meaningless to talk about trends over
time intervals of a decade or less. Year-to-year fluctuations in global temperature are simply too
large to establish a statistically significant warming (or cooling) trend over such a short time frame.
One can find many instances in which the undeniable warming trend of the past century would not be
evident in such short subintervals. 25
Despite the thorough falsehood of the “global warming has stopped” claim, it would
increasingly be hyped by climate change deniers during the run-up to the December 2009 Copenhagen
climate summit. The claim was the centerpiece of a September 30, 2009, Washington Post op-ed,
“For Alarmists, Ugly Truths on Global Warming,” by conservative columnist George Will , for
example, and shortly thereafter in an October 9, 2009, news story entitled “What Happened to Global
Warming?” by contrarian BBC reporter Paul Hudson. The claim was even featured in the topic
Superfreakonomic s released in October 2009. The “global warming has stopped” blitz of
misinformation and confusion led AP reporter Seth Borenstein to take the initiative of digging a bit
deeper. Borenstein engaged in some old-fashioned investigative journalism and contacted leading
statisticians, asking them, in a blind experiment (they were given the global temperature series, but
weren't told the source of the data or what it represented), if there was indeed any evidence to justify
the claim that the upward trend in the series of measurements had stopped. The answer in every case
was no. 26
Heads of the Hydra of climate change disinformation are often quickly generated thanks to a
single, deeply flawed paper that has slipped through the cracks of peer review. Take, for example, a
December 2007 paper by David Douglass, John Christy, Ben Pearson, and S. Fred Singer 27 claiming
to contradict an earlier 2005 Science article by Ben Santer and collaborators 28 establishing a human
role in the warming of the tropical atmosphere. It took only a week for other scientists to
demonstrate 29 that the Douglass et al. paper's principle claim arose from a simple misunderstanding
of the concept of statistical uncertainty. 30 Within a year, Santer et al. had published a devastating
critique, 31 showing that Douglass et al.'s approach gives clearly nonsensical results when applied to
a climate model simulation where the cause of temperature trends are known. This was not before
Douglass and his coauthors were able to milk a large amount of publicity with their claims, however.
Shortly after the publication of their paper, for example, S. Fred Singer held a press conference at the
 
 
 
 
 
 
 
 
 
 
 
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