WASHINGTON The world's sea levels could rise
twice as high this century as U.N. climate scientists have
predicted, according to researchers who looked at what happened
more than 100,000 years ago, the last time Earth got this hot.
Experts working on the U.N.'s Intergovernmental Panel on
Climate Change have suggested a maximum 21st century sea level
rise -- a key effect of global climate change -- of about 32
But researchers said in a study appearing on Sunday in the
journal Nature Geoscience that the maximum could be twice that,
or 64 inches.
They made the estimate by looking at the so-called
interglacial period, some 124,000 to 119,000 years ago, when
Earth's climate was warmer than it is now due to a different
configuration of the planet's orbit around the sun.
That was the last time sea levels reached up to 20 feet (6
meters) above where they are now, fueled by the melting of the
ice sheets that cover Greenland and Antarctica.
The researchers say their study is the first robust
documentation of how quickly sea levels rose to that level.
"Until now, there have been no data that sufficiently
constrain the full rate of past sea level rises above the
present level," lead author Eelco Rohling of Britain's National
Oceanography Centre said in a statement.
Rohling and his colleagues found an average sea level rise
of 64 inches each century during the interglacial period.
Back then, Greenland was 5.4 to 9 degrees Fahrenheit warmer
than now -- which is similar to the warming period expected in
the next 50 to 100 years, Rohling said.
Current models of ice sheet activity do not predict rates
of change this large, but they do not include many of the
dynamic processes already being observed by glaciologists, the
(Editing by Xavier Briand)