climate change and the cryosphere

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Climate change and the cryosphere

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Outline

• Background, climatology & variability• Role of snow in the global climate system• Contemporary observations of climate change • Cryospheric indicators of climate change• Future global & regional projections &

implications of climate change

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Background, climatology & variability

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20th Century ClimatologyObserved GFDL

Ref: Masuda

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Current snow

coverage

1 April 2013

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Departure from

average

1 April 2013

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Seasonal climatology

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Observed & GFDL Northern Hemisphere Snow Extent (x106 km2), 1973-2000

Season OBS GFDL MAE RMSE

Winter 44 42 2.4 0.55

Spring 30 35 4.8 1.00

Summer 6 4 2.3 0.51

Fall 19 20 1.7 0.40

Annual 25 25 0.9 0.22

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Mean annual maximum

monthly snow water

equivalent (mm) in

Canada, 1980-1997

(Brown et al. 2003)

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Current SWE in the Prairies

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Monthly Eurasian standardized snow cover extent anomalies

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Interannual variability

Source: Karl et al. (1993).

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Role of snow in the global climate system

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Annual cycle of daily discharge in Skeena River (1955-2004)

freshet

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Contribution of snow to river runoff

Source: Barnett et al. (2005).

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Teleconnections

Definition: Atmospheric interactions between widely separated regions that have been identified through statistical correlations (in space and time). For example, the El Niño teleconnection with the Southwest United States involves large-scale changes in climatic conditions that are linked to increased winter rainfall.

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Correlation coefficient between annual Eurasian snow extent anomalies & discharge anomalies

the following year in 64 rivers of northern Canada

Source: Déry et al. (2005), JGR.

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Observed 20th century climate change

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Warming air temperatures

Climatic Research Unit, University of East Anglia, http://www.cru.uea.ac.uk/

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20th century climate & trends

Reference: Déry and Wood (2005)

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Trends in global surface air temperature

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Trends in global surface precipitation

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Cryospheric indicators of global change

• Snow depth, swe, density, albedo & temperature (heat content)

• Duration of snow cover & growing season

• Snowmelt/spring freshet date

• Soil moisture

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Snow depth

Source: Curtis et al. (1998), Int. J.

Climatology

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Annual cycle of daily snow accumulation (SWE) at Barkerville

0

50100

150200

250300

350400

450

Date

Aver

age

annu

al c

ycle

of

dail

y SW

E (m

m)

1971-1977 1996-2005

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Trend (%) in April 1st swe, 1950-

1997

Source: Mote et al. (2005), BAMS

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Albedo

Source: Stone et al. (2002), JGR.

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Trend (days/year)

in snow cover

duration, 1972-2000

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Snowmelt Date

Source: Stone et al. (2002), JGR.

34Reference: Déry and Brown (2007)

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Annual cycle of daily runoff for the Little Swift River near Barkerville

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Trend in centre of volume in river discharge across western N. America

Source: Stewart et al. (2005), J. Climate.

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Future projections & implications of global change

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Components of the climate system

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IPC

C 4th A

ssessment

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IPCC 4th Assessment

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Expected indicators of climate change

IPCC 3rd Assessment

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IPCC 4th Assessment

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IPCC 4th Assessment

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IPCC 4th Assessment Runs

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Trends in Northern Hemisphere snow cover extent

Source: Déry et al. (2006), JGR.

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Projected change in seasonal snow cover frequency based on GFDL

CM2 simulations (21st - 20th century)

Projected change in frequency-0

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Trends in Northern Hemisphere snow mass

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Projected change in seasonal snow water equivalent (swe) based on

GFDL CM2 simulations (21st - 20th century)

Projected change in swe (mm)

-1

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Regional climate (baseline)

• Source: PCIC (http://www.pcic.uvic.ca)

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Temperature Projections

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Precipitation projections

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Regional Projections for snow

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Implications of global change

• Increase in planetary albedo (positive feedback on global warming)

• Decreasing water resources, including soil moisture

• Longer growing season

• Impacts on recreational activities

• Ecological implications

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Further reading:

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Points of Discussion:

• Which component of the cryosphere is most vulnerable to climate change?

• What are the possible environmental impacts of climate change in Prince George, B.C., Canada?

• Will there be any jobs for cryospheric scientists in the 21st century?