ARCTIC SEA ICE COVERSeptember 2005

NASA

SEA ICE EXTENTMarch 2006

MaximumSeptember 2006

Minimum

NEW RECORD!

2006: At or near record minimum in summer and winter

SEA ICE EXTENT

Max. Extent: 2.5% per decadeMin. Extent: 8.9% per decade

1979-2006: Decreasing trend

UCAR, Holland et al., 2006

The Road Ahead?

Ice-free summers in foreseeable future

SEA ICE COVERaka ‘The Great Integrator’

Ocean heat flux

Solar radiation

THERMODYNAMICSIce grow, melt and decay

Ocean stress

Wind stress

DYNAMICSIce motion

Reflects impact of atmospheric and oceanic forcing

Arctic Oscillation (AO)Two Dominant Regimes

• Colder winter temperatures• Strong Beaufort Gyre

• Warmer winter temperatures• Transpolar Drift Stream

sweeps ice out of Arctic Ocean

Negative AO Positive AO

ICEGAINS

ICELOSES

Atmospheric Oscillation (AO)

Strong positive pattern dominated from 1989 – 1996Favors loss of sea ice

More neutral pattern from 2000 - 2006Opportunity for recovery

Arctic Surface Air Temperature1900- 2006

Arctic-wide, annual averaged SAT anomalies (60 – 90°N) over land

1980-present: Warming trend

Warming: Arctic trend consistent with global trend

• March-May temperature anomaly composites • Relative to a 1968-1996 base period

SURFACE TEMPERATURE

Despite shift, positive (warm) anomalies remain over the entire Arctic

Southeastern Bering Sea continental shelf mooring

OCEANTemperature

2006: Significant cooling compared to previous 6-years

• Anomalies relative to EWG climatology (1950-1980s)

• NPEO surveys & J-CAD 

Morison et al., 2006a

OCEANNorth Pole Region

2000-2005:

Relaxation to near pre-1990 climatology

2000

2005

Salinity Temperature

Temperature & Salinity

2006 Arctic Report CardSea Ice Cover

• Arctic Oscillation

• Surface Temperature

• Ocean Temperature

Why continued decrease in extent?

Absorbedsunlight Lower albedo

Melting

Absorbedsunlight

Melting

Lower albedoAbsorbedsunlight

Melting

Lower albedo

+

++Positive

Feedback Cycle

Rigor and Wallace, 2004

Sep 2006

Canada

Alaska

Russia

Older, thicker ice

Sep 1987

Younger, thinner ice

SEA ICE AGE(Think thickness)

1988-1990: Precipitous decrease in thick ice

OW 0 1 2 3 4 5 6 8 10+ Years

Age:

PERENNIAL SEA ICEOlder, thicker ice

1950 1960 1970 1980 1990 2000 20102.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Year

Modeled QuikScat

Per

enni

al ic

e ar

ea (

106 k

m2 )

Rigor & Nghiem

Significant decrease in older ice

Strong & Persistent Positive AO

Sea ice cover susceptible to loss

Strong & PersistentPositive AO

(Less sea ice)

+Rising GlobalTemperature

Absorbedsunlight Lower albedo

Melting

+

++

Strong Positive Feedback Cycle

+

Confluence of Events…

State of the Arctic Sea Ice Cover

Summary• System under stress• Destabilization?

Arctic Oscillations Index

Through mid - 1990s:AO index effective predictorof trends in sea icecharacteristics

1989-1996: Strong positive AO2000s:

• AO shifted back to more neutral state• Sea ice not following suit

– Continued reduction in sea ice extent – Continued reduction in amount of older, thicker ice

Will system rebound?or

Has a ‘tipping’ point been reached?

International Polar Year

http://www.ipy.org/

IMPACT OF IPY2007-2008

June 2006

34 Platforms Reporting

May 2007

>150 Platforms Reporting