Climatic change in the Alps

Transcription

1 Climatic change in the Alps Prof. Martin Beniston Wengen-2006 Workshop

2 Overview Introduction Current and future climate in the Alps Potential impacts Conclusions

3 1 Introduction Current and future climate in the Alps Potential impacts Conclusions

4 The Alps are at the crossroads of numerous weather regimes Polar Continental Atlantic Mediterranean Saharan

5 Evolution of global and alpine temperatures, Beniston, M., 2004: Climatic Change and Impacts: An Overview Focusing on Switzerland. Kluwer Academic Publichers, 296 pp. 1.5 Global 1 Alps Change in T relative to [ C]

6 2 Introduction Current and future climate in the Alps Potential impacts Conclusions

7 Summer temperatures in Basel, Beniston, M., 2004: Geophys. Res. Letters Switzerland, Summer Tmax anomaly (Departures from means [ C]

8 Summer rainfall in the central Swiss Alps Precipitation anomalies [mm] Temperature anomalies [ C] Engelberg Altdorf St Gallen C C 0 0 C C

9 Climate futures 6.0 ΔT with respect to 20t h century [ C] A2 B2 IPCC, 2001 Mann et al., GRL, 1999

10 Changes in summer Tmax (june-july-august) (Differences between and ) (HIRHAM Regional Climate Model; A2 Scenario) Mean 90% quantile EU-PRUDENCE Project, University of Fribourg C

11 Tmax mean and 90% quantiles for current and future climates in Basel % quantile Average A2 B Beniston and Diaz, 2004: Global & Planetary Change

12 Changes in summer precipitation (JAS) (Difference in % between and ) (HIRHAM Regional Climate Model; A2 Scenario) Seasonal precipitation Precipitation > 50 mm/day % change Christensen, J. H. and Christensen, O. B., Nature, 2003

13 (B2) (A2) Changes in seasonal precipitation in the Alps (HIRHAM RCM) Seasonal precipitation [mm] Annual: 1605 mm Annual: 1591 mm Annual: 1597 mm Beniston, GRL, Winter Spring Summer Autumn

14 3 Introduction Current and future climate in the Alps Potential impacts Conclusions

15 Environment and Society: subtle linkages Environment Hydrological cycle Cryosphere Slope stability Biosphere Tourism Hydropower Society Safety of mountain communities Communication routes Mountain agriculture

16 Glacier retreat: Tschierva Glacier, Engadine Courtesy: Max Maisch University of Zürich, Switzerland +3 C? 2050? 2000

17 Changes in snow duration Duration [days] Mean winter precipitation [mm/day] Beniston, M., et al., 2003: Theor. & Appl. Clim Säntis (2,500 m): Current climate Arosa (1,600 m): Current climate Säntis: Future climate Arosa: Future climate Mean winter temperature [ C]

18 Changes in runoff in the central Alps (HIRHAM RCM) Mean 30-year runoff [mm/day] Winter Spring Summer Autumn +90% -5% -45% -20% Enhanced flood risk Enhanced drought risk Calendar day

19 Changes in extreme (B2) (A2) precipitation in the Alps (HIRHAM RCM) Number of evets beyond 99% quantile events 127 events 141 events Beniston, GRL, Winter Spring Summer Autumn

20 Consequences for floods: the buffering effects of snow Runoff Flood level

21 Examples of short-lived catastrophic events

22 Disturbance to Alpine vegetation From this to this?

23 4 Introduction Current and future climate in the Alps Potential impacts Conclusions

24 Pressures on socio-economic systems The Alps are a region with a high population density, high-value economic activity and expensive infrastructure Climate-induced disruptions to the natural environment will have significant impacts on socioeconomic systems Lack of snow winter tourism Changes in seasonality of runoff hydropower Extreme events and geomorphologic risks enhanced costs for the insurance industry Changes in heat and moisture régimes disruptions to ecosystems and agriculture

25 Prof. Martin Beniston Wengen-2006 Workshop