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

3

Kwok & Untersteiner (2011)

Sattellite Observations, “Best 17 models”

September Ice Extent, new IPCC models

Stroeve et al. (2012)

(updated for 2013)

5

National Snow and Ice Data Centre

1981 – 2010

Median

Ice Extent, June 23. 2014

March Trends: 1979-2011 Representative for

December - May

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

September Trends: 1979-2011

Representative for

June - November

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%

Sea Ice Age

(simulations)

1981 - 2007

www-nsidc.colorado.edu

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 %

Simulated sea ice extent in 2100, RCP2.6 (fraction, year 2000, year 2100)

March September

Simulated sea ice extent in 2100, RCP8.5 (fraction, year 2000, year 2100)

March September

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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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