Climatic change in the Alps Prof. Martin Beniston Martin.Beniston@unige.ch Wengen-2006 Workshop
Overview Introduction Current and future climate in the Alps Potential impacts Conclusions
1 Introduction Current and future climate in the Alps Potential impacts Conclusions
The Alps are at the crossroads of numerous weather regimes Polar Continental Atlantic Mediterranean Saharan
Evolution of global and alpine temperatures, 1901-2000 Beniston, M., 2004: Climatic Change and Impacts: An Overview Focusing on Switzerland. Kluwer Academic Publichers, 296 pp. 1.5 Global 1 Alps 0.5 0-0.5-1 Change in T relative to 1961-1990 [ C] -1.5 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
2 Introduction Current and future climate in the Alps Potential impacts Conclusions
Summer temperatures in Basel, Beniston, M., 2004: Geophys. Res. Letters Switzerland, 1901-2004 Summer Tmax anomaly (Departures from 1961-1990 means [ C] 7 6 5 4 3 2 1 0-1 -2 1947 1952 2003 2006-3 1901 1911 1921 1931 1941 1951 1961 1971 1981 1991 2001
Summer rainfall in the central Swiss Alps Precipitation anomalies [mm] Temperature anomalies [ C] 200 150 Engelberg Altdorf St Gallen 2005 +2 C 100 50 +1 C 0 0 C -50-100 -1 C 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Climate futures 6.0 ΔT with respect to 20t h century [ C] 5.0 4.0 3.0 2.0 1.0 0.8 0.6 0.4 0.2-0.2 0-0.4 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2050 2100 A2 B2 IPCC, 2001 Mann et al., GRL, 1999
Changes in summer Tmax (june-july-august) (Differences between 2071-2100 and 1961-1990) (HIRHAM Regional Climate Model; A2 Scenario) Mean 90% quantile EU-PRUDENCE Project, University of Fribourg +2 +4 +6 +8 +10 +12 C
Tmax mean and 90% quantiles for current and future climates in Basel 45 40 35 30 25 20 1961-1990 90% quantile Average 1980 1975 1970 1965 1960 1985 2070 2075 A2 B2 2080 2085 2003 2003 2071-2100 2100 2095 2090 Beniston and Diaz, 2004: Global & Planetary Change
Changes in summer precipitation (JAS) (Difference in % between 2071-2100 and 1961-1990) (HIRHAM Regional Climate Model; A2 Scenario) Seasonal precipitation -40-30 -20-10 0 +10 +20 +30 +40 Precipitation > 50 mm/day % change Christensen, J. H. and Christensen, O. B., Nature, 2003
1961-1990 2071-2100 (B2) 2071-2100 (A2) Changes in seasonal precipitation in the Alps (HIRHAM RCM) Seasonal precipitation [mm] 500 450 400 350 300 Annual: 1605 mm Annual: 1591 mm Annual: 1597 mm Beniston, GRL, 2006 250 Winter Spring Summer Autumn
3 Introduction Current and future climate in the Alps Potential impacts Conclusions
Environment and Society: subtle linkages Environment Hydrological cycle Cryosphere Slope stability Biosphere Tourism Hydropower Society Safety of mountain communities Communication routes Mountain agriculture
Glacier retreat: Tschierva Glacier, Engadine Courtesy: Max Maisch University of Zürich, Switzerland +3 C? 2050? 2000
Changes in snow duration 10 9 300 Duration [days] Mean winter precipitation [mm/day] Beniston, M., et al., 2003: Theor. & Appl. Clim. 8 7 6 5 4 3 2 Säntis (2,500 m): Current climate 2071-2080 Arosa (1,600 m): Current climate 2081-2090 Säntis: Future climate 2091-2100 Arosa: Future climate 1-8 -7-6 -5-4 -3-2 -1 0 1 2 3 Mean winter temperature [ C] 2071-2080 75 2081-2090 2091-2100 350 325 300 275 250 225 200 175 150 125 100 75 50 25
Changes in runoff in the central Alps (HIRHAM RCM) Mean 30-year runoff [mm/day] 6 5 4 3 2 1 Winter Spring Summer Autumn +90% -5% -45% -20% 2071-2100 Enhanced flood risk Enhanced drought risk 1961-1990 0 1 31 61 91 121 151 181 211 241 271 301 331 361 Calendar day
1961-1990 Changes in extreme 2071-2100 (B2) 2071-2100 (A2) precipitation in the Alps (HIRHAM RCM) Number of evets beyond 99% quantile 70 60 50 40 30 20 108 events 127 events 141 events Beniston, GRL, 2006 10 0 Winter Spring Summer Autumn
Consequences for floods: the buffering effects of snow Runoff Flood level
Examples of short-lived catastrophic events
Disturbance to Alpine vegetation From this to this?
4 Introduction Current and future climate in the Alps Potential impacts Conclusions
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
Prof. Martin Beniston Martin.Beniston@unige.ch Wengen-2006 Workshop