Ice cores, global warming and rising seas
Jan. 25, 2013
Jim White
A new deep ice core study by an international team of scientists involving the
University of Colorado Boulder discovered that between 130,000 and 115,000
years ago the climate in north Greenland rose to about 14 degrees Fahrenheit
warmer than today.
The ice cores come from a time known as the Eemian interglacial period and,
according to CU-Boulder geological sciences Professor Jim White, an ice core
expert and the lead U.S. investigator on the project, the findings indicate the
last interglacial period may be a good analog for where the planet is headed
in terms of global warming.
CUT 1 “The NEEM ice core was the first ice core in which we recovered a full
record of the last interglacial period. The last interglacial period is our best
analog for a warmer future and so it was a real goal for us to get a good
record of that time period from Greenland. (:16) Given the amount of
greenhouse gas in the atmosphere today no one expects us to avoid a
warmer planet. The last inter-glacial period is becoming more and more of a
reality for us sometime in the next century.” (:28)
The ice cores go back in time more than 100,000 years. What the NEEM
scientists fond is that despite the strong warming signal during the Eemian a period when the seas were roughly 15 to 25 feet higher than today - the
surface of the ice sheet near the drilling facility was only a few hundred yards
lower than it is today, an indication that Greenland contributed less than half
of the total sea rise at the time.
CUT 2 “I think one of the key findings in the NEEM paper is that West
Antarctica was a major player during the last interglacial period. The
importance of that is that the West Antarctic Ice Sheet is an ice sheet whose
base is well below sea level. (:15) And so when it starts to melt it can go very
rapidly -much faster than Greenland can add to sea level. The rate at which
sea level rises is a critical piece of information that we really don’t have our
hands around yet.” (:29)
Getting a better idea of the role the West Antarctic Ice Sheet played during
the last interglacial period is vital, says White.
CUT 3 “And what the NEEM study has shown is that we really do have to pay
attention to West Antarctica. And we do have to pay attention to the fact that
sea level may rise 10, 15 times faster than it has in the past 100 years. (:13)
And that would be a shock to our economy, to our coastal cities, to
infrastructure. It would be something we would have to adapt to and that
adaptation would not be cheap.” (:26)
White says given the strong possibility that we are headed toward warmer,
Eemian-like conditions means we should explore ways to remove carbon
dioxide from the atmosphere. If we don’t he says there is so much CO2 in the
atmosphere that it will take centuries for it to dissipate on its own.
CUT 4 “One of the realities of producing carbon dioxide is that is stays in the
atmosphere for hundreds of years, if not thousands of years. (:08) So unless
we purposely take it out of the atmosphere and find a way to store it,
whether that’s underground in carbon vaults - an expensive but not an
impossible proposition - unless we’re wiling to do that than the planet will
warm and it will continue to warm and we will go into a climate state the
likes of which the planet has not seen for millions of years. (:29)
The NEEM deep ice core drilling project involves 300 scientists from 14
countries and is led by the University of Copenhagen.
-CU-