Arctic sea ice extent reaches new low in satellite history
- 29 Aug 2012, 11:30
- Carbon Brief staff
Last week, a number of institutions announced that sea ice in
the Arctic had reached its lowest since satellite records began in
1979. The Danish
Meteorological Institute, the Japan
Aerospace Exploration Agency and the Norwegian
Arctic ROOS all announced that according to their measurements,
a record low had been reached.
These records had by and large failed to make the news until the
prominent US research group the National Snow and Ice Data Centre
(NSIDC)
reported on Monday that daily extent is now the lowest in the
satellite era. It says:
"Arctic sea ice extent fell to 4.10
million square kilometers (1.58 million square miles) on August 26,
2012. This was 70,000 square kilometers (27,000 square miles) below
the September 18, 2007 daily extent of 4.17 million square
kilometers (1.61 million square miles)."
Since it measures sea ice minimum extent over the course of the
month, NSIDC says its announcement isn't yet official. But that
didn't stop almost every major media outlet from reporting the
figures.
The media covers it
To find out what the new record low might mean for climate change,
most outlets asked scientists.
Weather in the region affects how the ice melts. Both
The Independent and
The Guardian, quoting Mark Serreze at NSIDC, report that beyond
an early storm in August, weather patterns this summer have not
been out of the ordinary, but after many years of warming "the ice
is so thin and weak now, it doesn't matter how the winds
blow."
Newer ice that is only one winter old is much thinner than ice
that has been present for many years. Speaking to research
scientists at NASA, The
BBC explains that numerous warm years have reduced the amount
of multi-year ice cover, leaving summer ice thinner and vulnerable
to break up. This effect means that it's more likely that the ice
will reach record lows, even without the poor weather conditions
experienced in 2007 when the previous record was set.
While all coverage made the link to climate change in some way,
The Telegraph reported scientist Michael Mann from Penn State
University saying that these changes are happening faster than
climate models predicted. Meanwhile, modelling that assesses sea
ice volume suggests that 2012
has also seen a new low over the same timescale.
Asking scientists
There are dissenting voices - notably from the same small group of
scientists who usually disagree with the scientific community on
climate.
The Sunday Times argues that "some scientists are being more
cautious" about interpreting these figures. Citing John Christy
from the University of Alabama, who suggests that the climate is
not particularly sensitive to carbon dioxide, the article says that
anecdotal evidence proves similar warming periods have occurred and
that its difficult to separate climate change and natural
variability.
The
Washington Post cites Patrick Michaels of US thinktank the Cato
Institute, who argues: "The overall loss in sea ice from the planet
is less than people often assume," and claims that sea ice has been
expanding at the South Pole. But other climate skeptics have
suggested
such arguments are weak.
Watts Up With That attributes the record low to the early
August storm, and claims that NSIDC's data-gathering method is old
and unreliable. Walt Meier from the NSIDC responds to these claims
in comments, explaining why the satellite monitoring system used is
the best for identifying year-to-year variations.
With all this interest, expect to see more coverage, particularly
when NSIDC announce that the sea ice has reached its minimum extent
- some time in the next few weeks. In the Washington Post,
meanwhile, Brad Plumer has produced an eight point list on why he
thinks the
new record melt matters.