Changing risks in a changing climate

Transcription

1 Changing risks in a changing climate Martin Beniston Head, Environmental Science Dept. University of Geneva, Switzerland Martin.Beniston@unige.ch ENSEMBLES Workshop, Venice,

2 Outline of the presentation Introduction Definitions of extremes Changes in a future climate Impacts related to extremes Conclusions

3 1 Introduction Definitions of extremes Changes in a future climate Impacts related to extremes Conclusions

4 Earthquakes Storms Floods Other MunichRe billion-dollar hazards, % Number of events Victims (thousands) Economic losses (billions US$) Insured losses (billions US$)

5 Number of events MunichRe billion-dollar climaterelated hazards Total losses Insured losses Costs in billion $US (1999)

6 2 Introduction Some definitions of extremes Changes in a future climate Impacts related to extremes Conclusions

7 What is a climatic extreme? A rare event? Approaches based on frequency of occurrence

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

9 What is a climatic extreme? A rare event? Approaches based on frequency of occurrence An intense event? Approaches based on threshold exceedance

10 Exceedance of 30 C and 35 C thresholds in Basel in summer Tmax [ C] June July August Julian Day (2003)

11 What is a climatic extreme? A rare event? Approaches based on frequency of occurrence An intense event? Approaches based on threshold exceedance An extreme with respect to the impacts? Need to deal with the vulnerability and adaptability of systems An extreme impact is not always associated with a weather extreme!

12 Coastal vulnerability to sea-level rise in the southeasern United States 1m 2m Charleston New Orleans Over persons at risk! Tampa/ St Petersburg Miami Fort Myers

13 An example of an extreme event: rare (hopefully!) and damaging Tacoma Narrows Bridge, USA November 7, 1940

14 Where do extremes come from? Amplification of perturbations embedded within the general atmospheric circulation Modulation of «normal weather» by decadalscale climate variability (ENSO, NAO, AO, ) Enhancement of the energy required to trigger extremes by a warmer climate forced by increased atmospheric greenhouse-gas concentrations

15 PDFs and Frequency of occurrence 30% 20% extremes Symmetrical shift Change in shape (variance and kurtosis) 10% 0% C

16 3 Introduction Definitions of extremes Changes in a future climate Impacts related to extremes Conclusions

17 Climate futures IPCC, 2007 Mann et al., GRL, A Ecart par rapport au 20e siècle [ C] B2

18 Changes in extremes of heat (summer) (Difference between and ) (HIRHAM Regional Climate Model; A2 Scenario) Conditions caniculaires M. Beniston, 2004: Geophysical Rsearch Letters C

19 Changes in extremes of precipitation (summer) (Difference between and ) (HIRHAM Regional Climate Model; A2 Scenario) % Christensen and Christensen, Nature, 2003

20 Number of evets beyond 99% quantile (B2) (A2) 108 events 127 events 141 events Changes in extreme precipitation in the Alps (HIRHAM RCM) Beniston, 2006, Geophys. Res. Letters 0 Winter Spring Summer Autumn

21 Tropical storms 160 Cat 3 Cat 4 Cat Number of events Pressure at center of system [hpa] Rainfall totals [mm/6 h] K. Emmanuel, Science: 2006

22 4 Introduction Definitions of extremes Changes in a future climate Impacts related to extremes Conclusions

23 Coastal zones at risk by km2 (4%) km2 (6%) 600 km2 (2%) km2 (1%) Costs of coastal protection Netherlands: 12 bn Germany: 23 bn Poland: 1,5 bn

24 Number of days > 30 C (HIRHAM RCM A2 Scenario) 2.a Difference 2.b Beniston, 2004: Geophysical Reserch Letters days

25 Mortality in Paris: 2003 heat wave C Mortality (anomaly) Tmax Tmin Fouillet et al., 2006: Env. Health

26 Impacts on mortality by 2050 Respiratory diseases Cardiovascular diseases +5% +0% IPCC, % Athens Amsterdam

27 Damage to European agriculture during the 2003 heat wave Hay Wheat Corn France 4 bn Germany 1,5 bn Italy 4,5 bn Spain 0,8 bn -60% -40% -20% 0% +10% Changes in yields

28 Agricultural production by 2100? +5% +10% +15% +25% +25% 0% -10% +5% -20% +5%

29 Futurs hydrologic risks Flooding Drought + fires

30 Consequences for floods

31 Alpine flood events

32 Receding snow and ice: Tschierva Glacier, Engadine +3 C? 2050? 2000 Courtesy: Max Maisch University of Zürich, Switzerland

33 Impacts on winter tourism Austria Switzerland Germany France Italy Altitude [m sur mer] Severe impacts Moderate impacts OECD ALPS REPORT, 2007

34 5 Introduction Definitions of extremes Changes in a future climate Impacts related to extremes Conclusions

35 Linking climate and costs: a question of scale Type of extreme Spatial scale of event Spatial scale of impact Time scale of event Time scale of impact Winter wind storms System: 1,000 km Track: > 1,000 km Individual buildings to large areas along storm track 1 day A few seconds to several years after the event Heat waves, cold spells 100 km 2 >1,000,000 km 2 From persons to large areas > 3 days Comparable to the duration of the event Extreme precipitation 1 km 2 10,000 km 2 Individual buildings to large areas Minutes to hours A few minutes to a few hours Floods 1 km 2 > 10,000 km 2 Individual buildings to large areas Minutes to months A few minutes (flash floods) to several weeks after the event Hail 1 km 2 10 km 2 Cars, buildings, to large agricultural surfaces Minutes A few seconds to weeks after the event Drought 100 km 2 >1,000,000 km 2 Comparable to the scale of the event Days to months Days to months after the event

36 Many thanks for your attention ENSEMBLES Workshop, Venice,