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SCIENCESaturday 12 March 2016
Panel: Finding climate fingerprints in wild weather is valid
SETH BORENSTEIN In this July 21, 2010 file photo, a polar bear has a bucket on his head, while cub polar bear swims on the board of Climate
AP Science Writer nearby in the cooling waters of Moscow Zoo. Central, which manages
WASHINGTON (AP) — Cli- a large climate attribution
mate science has pro- Associated Press project.
gressed so much that Good attribution studies
experts can accurately they were more likely or report. severe thunderstorms are are based on what Titley
detect global warming’s more severe because of “For a certain class and on the low end of the con- calls a “three-legged stool”
fingerprints on certain ex- man-made global warm- type of event there is a fidence range, the report of observational records of
treme weather events, ing, said academies report human fingerprint,” said found. decades of past events,
such as a heat wave, ac- chairman David Titley, a report co-author Marshall In some cases heat and detailed understanding of
cording to a high-level sci- Pennsylvania State Univer- Shepherd, a University of lack of rain combine, the physics that cause the
entific advisory panel. sity meteorology professor. Georgia meteorology pro- and the studies find a vi- weird weather itself, and
For years scientists have And that matters. fessor. The report says there able connection to global sophisticated computer
given almost a rote re- “While we plan for climate, is “high confidence” in warming, such as in the models that simulate the
sponse to the question of we live in weather,” Titley, a studies looking for climate recent four-year California chances of the extreme
whether an instance of retired Navy admiral, said change connections be- drought and the drought event if there were no
weird weather was from in an interview. “These ex- tween extreme hot and that hit Syria and its neigh- man-made, heat-trapping
global warming, insisting tremes are making climate cold temperatures, such as bors, Titley said. gases warming the atmo-
that they can’t attribute real when in fact they are the Russian heat wave of “The fog of uncertainty sphere.
any single event to cli- attributable to climate 2010. There’s medium con- that obscured the human These studies don’t say
mate change. But “the sci- change.” fidence in efforts trying to role in individual events is fi- an event was 100 per-
ence has advanced to the Not all weird weather can attribute droughts and ex- nally lifting,” said Princeton cent caused by climate
point that this is no longer be blamed with any de- treme rainfall. University professor Michael change. They usually say
true as an unqualified blan- gree of certainty on global Hurricanes and other tropi- Oppenheimer. He wasn’t chances were increased
ket statement,” the Nation- warming, according to the cal cyclones, wildfires and part of the study, but is by a certain fraction.
al Academies of Sciences, Katharine Hayhoe, a Texas
Engineering and Medicine Tech climate scientist who
reported. wasn’t part of the study,
Starting in 2004, dozens of praised the work: It is “very
complex peer-reviewed important to clarify to peo-
studies found the odds of ple how no event is black or
some extreme events were white: No individual weath-
affected by man-made er event can be said to be
climate change. This new ‘solely’ human nor ‘solely’
field of finding global warm- natural any more. They are
ing fingerprints is scientifi- somewhere on the sliding
cally valid, the academies scale between.”
said in a 163-page report But other scientists don’t
released Friday. The private like the idea of looking at
non-profit has advised the single events.
government on complex, Climate change caused
science-oriented issues by man “has fingerprints in
since the days of President every weather event we
Abraham Lincoln. experience today,” wrote
When it comes to heat Oklahoma University me-
waves, droughts, heavy teorology professor Jason
rain and some other events, Furtado, who wasn’t part
scientists who do rigorous of the study. q
research can say whether
