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Causes of Arctic Sea Ice Loss and a Future Outlook:
Possible Effects on Fisheries and Navigation
CHALLENGES OF THE CHANGING ARCTIC:
CONTINENTAL SHELF, NAVIGATION, AND FISHERIES
Lars H. Smedsrud
Professor, Geofysisk Institutt
Friday 27. May 2014, Bergen, 09:00 – 09:15 (10 min for questions)
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Arctic icethickness Satellite based
2005-2007
Yearly means
Zygmuntowska et al (2014)
Snow Climatology [cm]
1954-1991 (winter: October-April)
Svarte linjer
Sattellite Observations, “Best 17 models”
September Ice Extent, new IPCC models
Stroeve et al. (2012)
(updated for 2013)
Observed ocean temperature since 1900
Barents Sea Ice loss driven by Atlantic Heat
March 2006 March 1979
Smedsrud et al (2013)
Explains much of the
Arctic Sea Ice Loss
during winter
Longest Temperature series in Arctic Ocean:
Kola Section
0
500
1000
1500
2000
2500
3000
3500
4000
4500
1946 1953 1960 1967 1974 1981 1988 1995 2002 2009
Barents Sea cod stock
Cod total stock
Cod spawningstock
The worlds largest cod stock
Increased in recent years
The spawning stock at alltime high
Shipping along Russia northern coast:
First supertanker (Vladimir Tikhonov)
sailed in 2011, cargo: 120,000
tonnes of gas condensate
Days saved from Kirkenes and Murmansk
Tschudi Shipping Company A/S
The Northern Sea Route
cuts Hamburg Yokohama
distance with 39%
2004-2009: 888.000 km² 1957-2010: 771.000 km²
Difference equals area of Austria : 84.000 km² + Switzerland 41.000 km²
[Kwok, 2009]
[Smedsrud et al 2011]
Fram Strait export: high since 2004
Arctic
Column
Model
Nansen’s new hat
Atmospheric
Transport
+3 W/m²
Ocean
Transport
+5 W/m²
(Smedsrud et al 2008)
“Direct effect”
of Global warming
Longwave radiation
+ 5 W/m²
Increase in ice
Export + 25 %
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Loss of area (summer ~50%) and thickness (3.5m => 1.8m)
Winter ice loss in Atlantic sector
Four main reasons for ice loss: Radiation (Global warming)
Atmospheric heat
Oceanic heat
Ice Export
Earth system models are “good enough”
An optimistic scenario “saves” the Arctic Sea Ice
Summary:
Abstract
Loss of Arctic sea ice has been documented for over 20 years, and is one of the most
visible signs of ongoing global warming. Today summer sea ice extent has declined by
about 50%, thickness hasreduced by about 40%, and the Northern Sea Route has
become navigational waters for a limited time during summer. In 2100 the most
pessimistic (business as usual) IPCC scenario has no summer ice left, while for the most
optimistic IPCC scenario the Arctic sea ice cover remains roughly at today's level. What
remains quite certain is that the "natural" variability will increase with a thinner ice cover,
and that there are a number of negative feed-back processes operating protecting the
ice, and preventing a so called "tipping-point" behaviour.
The principal causes of the sea ice loss that has occurred will be summarized, and the
scenarios for the future discussed.
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