WASHINGTON -- One of
the nation's most recognizable names in climate
science, Dr. James Hansen, released a new paper this
week warning that even 2 degrees Celsius of global
warming may be "highly dangerous" for
The paper, which will
be published online in the European Geosciences Union
Chemistry and Physics Discussion later this
week, projects sea levels rising as much as 10 feet in
the next 50 years.
The paper notes there
is evidence indicating that average temperatures just
1 degree Celsius warmer than today caused sea levels
to rise 16 to 30 feet and fed extreme storms thousands
of years ago.
Hansen and 16 co-authors
drafted the paper as a message to policymakers that
current greenhouse-gas reduction goals are not strong
enough. World leaders have committed to limiting
average warming to 2 degrees Celsius (3.6 degrees
Fahrenheit), a goal articulated
in the Copenhagen Accord in 2009 and reiterated
by G7 leaders in June.
"The message for
policymakers is that we have a global crisis that
calls for international cooperation to reduce
emissions as rapidly as practical," wrote the
Their projections are
based on an anticipated accelerated melting of ice
sheets in Greenland and Antarctica due to rising
atmospheric concentrations of heat-trapping greenhouse
gases. The melting ice sheets will put more cold,
fresh water into the oceans, changing circulation
patterns and ultimately causing even more melting of
the ice sheets -- thus causing sea levels to rise much,
much faster than other projections have forecast.
"We conclude that
continued high emissions will make multi-meter sea
level rise practically unavoidable and likely to occur
this century," the scientists wrote. "Social
disruption and economic consequences of such large sea
level rise could be devastating."
Hansen, who was the
director of NASA's Goddard Institute for
Space Studies until
April 2013 and is now an adjunct professor in the
Department of Earth and Environmental Sciences at
Columbia University, has been warning about climate
threats for years. He's moved from dispassionately
investigating the science to actively
advocating for specific solutions to the problem.
Holthaus at Slate put it, Hansen "is known
for being alarmist and also right."
The paper has already
ruffled some, including Associated Press science
writer Seth Borenstein, who said on Twitter that he
would not cover it -- primarily because it
had not yet been peer-reviewed, a process that allows
other scientists to critique the work.
Post's Chris Mooney asked other climate experts to
weigh in on the paper. While many said it raised key
discussion points, Kevin Trenberth of the National
Center for Atmospheric Research called it "provocative
and intriguing but rife with speculation and 'what if'