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A Swedish perspective on adaptation to Climate

Change

Jörgen Nilsson

Swedish Meteorological and Hydrological Institute

Norköping

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Nordic hydropower in % of total electricity

production

Norway 100% 123 TWh

Sweden 45% 66 TWh

Finland 12% 8 TWh

(approximate figures)

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Inflow to the Swedish hydropower reservoirs in relation to the

average for the period 1950-2006 (TWh/year)

Source: Svensk Energi-25

-15

-5

5

15

25

1950 1961 1972 1983 1994 2005

TWh/år

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We need regional information

Source: Monitor No. 18, 2003

300x300km 50x50km

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Precipitation change downscaled by the regional RCO:

HadAM3H

ECHAM4/OPYC3

Emission scenario A2 Emission scenario B2

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Annual runoff change (mm)

Hadley/A2

Annual runoff change (mm)

Echam/A2

Annual runoff change (mm)

Hadley/B2

Annual runoff change (mm)

Echam/B2

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National hydrograph for Sweden 1961-1990 vs

2071-2100

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Future production potential in Swedish rivers

1961-1990 vs 2071-2100

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Implications: Less demand for heating … but more for

coolingC

DD

HD

D

1961-1990 2011-2040 2041-2070 2071-2100

Heating degree days per year, T<17oCCooling degree days per year, T>20oC

A2

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Swedish guidelines on

hydrological design

of dams

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Upgrading of dam safety, new spillway for the

Håckren dam

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Impacts on design

floods in Sweden

% change in design flood peak, 1961-1990 vs 2071-2100

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Changes in 100-years floods according to E/A2 and E/B2

scenarios

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Changes in 100-years floods according to H/A2 and H/B2

scenarios

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The Nordic energy sector is very sensitive to global

warming:

•It effects production (inflow to hydropower, wind,

biomass)

•It effects consumption (heating)

•It effects safety (storms, dam safety)

•It effects distribution (storms)

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The most evident impact is that on hydropower,

impacts on wind power are more inconclusive

•Hydropower production is expected to increase

•The annual rythm in river flow will be more favorable

•Impact on dam safety is not self-evident and has to be

analysed carefully, case by case

•The development of the future European energy market

will have strong impact on the Nordic hydropower

industry

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The Swedish Commission on Climate and

Vulnerability

•Addresses impacts, vulnerability,

responsibilities and costs due to climate change

•Sub-report on flooding, November 2006

•Final report, October 2007

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Future flood risks around the big Swedish lakes

Stockholm

Gothenburg

KarlstadMälaren

HjälmarenVänern

VätternGöta älv

Örebro

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Stockholm 1924

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Stockholm in April 2003

Foto: Sten Bergström, SMHI

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Lake Mälaren and Stockholm, summary of the

problems

1. Decree for regulation in 1943

2. Pressure on exploitation, shore lines are not secure under

today’s climate. Important downtown infrastructure is at risk,

including the subway

3. Important shipping

But…

1. No river downstream hinders discharge

2. Sea level rise is compensated by uplift of land

3. Climate change does not seem to increase the problems

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Uplift of land in Sweden (mm per year)

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Large land slides in the Göta älv valley

5

3

1

12215

4

14(2)

8

9

6

167, 10 13

1: Jordfallsskredet 1150, 65 har

3: Intagan 1648-07-10, 27har

6: Ballabo mars 1733, 3 har

9: Utby 1806-12-21, 4,5 har

10: Västerlanda ca 1830, >5 har

12: Surte 1950-09-29, 24 har

14: Göta 1957-06-07, 32 har

15: Agnesberg 1993-04-14, 0,25har

16: Ballabo 1996-04-16, 0,7 har

Source: Statens Geotekniska Institut

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Inundated areas at

peak level if

Climate Change

is considered will

be about 50 cm

higher than today

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Change in 100-year levels(cm) New return periods

RCAO – H/A2 + 37 25

RCAO – H/B2 + 21 40

RCAO – E/A2 + 98 5

RCAO – E/B2 + 57 12

Changes in the 100-years levels and return periods for Lake Vänernaccording to climate scenarios

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Tunnel?

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Attractive near-shore developments in the city of Karlstad

Foto: Sten Bergström, SMHI

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Vänern- Göta älv, summary of the problems

1. Decree for regulation in 1937

2. Pressure on exploitation, shore lines are not secure

under today’s climate

3. Hydropower in the river

4. Important shipping

5. Unstable geology limits discharge in the river. Land

slides may risk water supply for 700 000 citizens

6. Sea levels hinder discharge

7. Climate change increases the problems

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Conclusions

•Big lakes mean big problems in metropolitan areas

•Today’s flooding problems will be aggravated by climate

change in western Sweden

•Stockholm can be secured by a doubling of the discharge

capacity of Lake Mälaren

•There is no simple solution for Lake Vänern and River

Göta älv. A combination of measures will be needed.

•Cautious physical planning is necessary to avoid future

problems everywhere

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How to handle all that unavoidable uncertainty?

•Use ensembles of climate models and scenarios

•Develop flexible adaptation strategies

•Add safety margins wherever reasonably possible

•Communicate!