[Reader-list] Twiddling our thumbs

[Nagraj Adve]

Yet again, reality is unfolding much faster than models predict. The Arctic
may seem very far away and remote but significant changes there will have
huge impacts on weather systems very widely.
Capital would be interested in freed up oil and gas, in easier sea routes,
etc.
What's our response going to be? Continue to twiddle our thumbs?
Naga

 Arctic may be ice-free within 30 years

Data showing dramatic sea ice melt suggests warming at the north pole is
speeding up
John Vidal <http://www.guardian.co.uk/profile/johnvidal>, environment editor


   - guardian.co.uk <http://www.guardian.co.uk/>, Monday 11 July 2011 16.42
   BST
   - Article history<http://www.guardian.co.uk/environment/2011/jul/11/arctic-ice-free#history-link-box>
    [image: Arctic ice cave]
   Arctic ice is melting at a record pace, suggesting the region may be
   ice-free during summer within 30 years. Photograph: Alexandra
   Kobalenko/Getty

   Sea ice in the Arctic <http://www.guardian.co.uk/world/arctic> is melting
   at a record pace this year, suggesting warming at the north pole is speeding
   up and a largely ice-free Arctic can be expected in summer months within 30
   years.

   The area of the Arctic ocean at least 15% covered in ice is this week
   about 8.5m sq kilometres – lower than the previous record low set in 2007 –
   according to satellite monitoring by the US National Snow and Ice Data
   Centre<http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png>(NSIDC)
in Boulder, Colorado. In addition, new data from the University of
   Washington Polar Science Centre, shows that the thickness of Arctic ice
   this year is also the lowest on
record<http://psc.apl.washington.edu/wordpress/wp-content/uploads/schweiger/ice_volume/BPIOMASIceVolumeAnomalyCurrentV2.png>
   .

   In the past 10 days, the Arctic ocean has been losing as much as 150,000
   square kilometres of sea a day, said Mark Serreze, director of the NSIDC.

   "The extent [of the ice cover] is going down, but it is also thinning. So
   a weather pattern that formerly would melt some ice, now gets rid of much
   more. There will be ups and downs, but we are on track to see an ice-free
   summer by 2030. It is an overall downward spiral."

   Global warming has been melting Arctic sea ice for the past 30 years at a
   rate of about 3% per decade on average. But the two new data sets suggest
   that, if current trends continue, a largely ice-free Arctic in summer months
   is likely within 30 years. That is up to 40 years earlier than was
   anticipated in the last Intergovernmental Panel on Climate
Change<http://www.guardian.co.uk/environment/climate-change>(IPCC)
assessment report.

   Sea ice, which is at its maximum extent in March and its lowest in
   September each year, is widely considered to be one of the "canaries in the
   mine" for climate change, because the poles are heating up faster than
   anywhere else on Earth. According to NSIDC, air temperatures for June 2011
   were between 1 and 4C warmer than average over most of the Arctic
Ocean<http://nsidc.org/images/arcticseaicenews/20110706_Figure4.png>
   .

   The findings support a recent study in the journal Science that suggested
   water flowing from the Atlantic into the Arctic ocean is warmer
today<http://dirwww.colorado.edu/news/r/9059018f4606597f20dc4965fa9c9104.html>than
at any time in the past 2,000 years and could be one of the
   explanations for the rapid sea ice melt now being observed.

   Computer simulations performed by Nasa suggest that the retreat of Arctic
   sea ice will not continue at a constant rate. Instead the simulations show a
   series of abrupt decreases such as the one that occurred in 2007, when a
   "perfect storm" of weather conditions coincided and more ice was lost in one
   year than in the previous 28 years combined. Compared to the 1950s, over
   half of the Arctic sea ice had disappeared.

   What concerns polar scientists is that thicker ice which does not melt in
   the summer is not being formed fast as the ice is melting. On average each
   year about half of the first year ice, formed between September and March,
   melts during the following summer. This year, says Jeff Masters, founder of
   the Weather Underground climate monitoring website, a high pressure system
   centred north of Alaska has brought clear skies and plenty of ice-melting
   sunshine to the Arctic.

   "The combined action of the clockwise flow of air around the high and
   counter-clockwise flow of air around a low pressure system near the western
   coast of Siberia is driving warm, southerly winds into the Arctic that is
   pushing ice away from the coast of Siberia, encouraging further melting."

   Sea ice has an important effect on the heat balance of the polar
oceans<http://www.guardian.co.uk/environment/oceans>,
   since it insulates the (relatively) warm ocean from the much colder air
   above, thus reducing heat loss from the oceans. Sea ice also has a high
   albedo – about 0.6 when bare, and about 0.8 when covered with snow –
   compared to the sea – about 0.15 – and thus the loss of sea ice increased
   the absorption of the sun's warmth by the sea.