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|Cores drilled from the icecap are going
on show at London's Science Museum. The centuries-old information
they contain could help scientists predict Earth's future weather.
They were found deep below Earth's surface, provide vital
information about our climate's history and, for the first time,
will be publicly displayed in their full freezing glory. Three
pieces of ice core, drilled from the Antarctic icecap, one
containing bubbles of air from the year 1410, will this week be
installed in a glass-fronted freezer cabinet in the Science Museum
in London's new Atmosphere gallery.
Set for its opening by Prince Charles on Friday, the gallery has
been designed to outline the basics of climate science and explain
why researchers believe human activity is now having a pronounced
impact on weather patterns. "This gallery will show how scientists
have acquired their knowledge about Earth's climate history – with
our ice cores providing some of the most telling examples," says
museum director Chris Rapley.
Air gets trapped by snow as it falls. Then more snow falls on top.
Pressure builds up and snow is eventually converted into ice – with
air bubbles trapped inside. The deeper you drill, the older the ice
– and air bubbles – that you find. "If you drill several kilometres
down you find samples that are almost a million years old," says
Rapley. "That is why we think of ice cores as treasure troves of
By drilling down to a particular layer, the oxygen isotopes in a
core sample's air bubbles will tell you the global temperature for
the time that the air was trapped in snowflakes. This temperature
can then be compared with the air's carbon dioxide content.
Similarly, salt and dust contamination provides information about
sea levels and the spread of deserts across the globe at any given
time over the last 800,000 years. Such information has been key to
the prediction of future global weather patterns and will form an
important background to this week's climate talks in Cancun, Mexico.
"The one critical feature we get from these measurements is that the
temperature of Earth's atmosphere and its carbon dioxide content are
locked together in a coupled system," adds Rapley. "If one of those
variables increases, the other will also rise. Hence the worry about
the amounts of carbon dioxide we pump into the atmosphere. If
unchecked, these could lead to global temperature rises of up to six
degrees Celsius by the end of the century."