World Meteorological Organization Working together in weather, climate and water

1. World Meteorological OrganizationWorking together in weather, climate and water WMO Impacts of Climate Change on water related risks AVINASH TYAGI Director, Climate and Water Department WORLD METEOROLOGICAL ORGANISATION Session 1.3.3: Managing water related risks in changing climate Fifth World Water Forum 16-22 March, 2009, Istanbul, TURKEY WMO: Climate and Water Department www.wmo.int

2. Introduction

3. What is global warming? “Global warming” refers to increases in global temperatures as a result of an accumulation of greenhouse gases in the atmosphere. Greenhouse gases, such as CO2 , CH4, N2O, HFCS,…

4. Precipitation form, timing and quantity Air temperature Sea level rise Potential Impacts of Climate Change

5. OBSERVATIONS

6. Global mean temperatures Warmest 12 years: 1998,2005,2003,2002,2004,2006, 2001,1997,1995,1999,1990,2000 50 0.1280.026 100 0.0740.018 Period Rate Years /decade

7. Sea level in 20th century SPM-3b • Rates of sea level rise: • 1.8 + 0.5 mm yr-1, 1961-2003 • 1.7 + 0.5 mm yr-1, 20th Century • 3.1 + 0.7 mm yr-1, 1993-2003

9. Increases Decreases Changes in Land precipitation Smoothed annual anomalies for precipitation (%) over land from 1900 to 2005; other regions are dominated by variability.

10. Between 18 and 21 mm/yr Between 21 and 27 mm/yr Between 27 and 30 mm/yr Between 30 and 36 mm/yr Wet Season Between -21 and -24 mm/yr Between -18 and -21 mm/yr Between -15 and -18 mm/yr Between -9 and -12 mm/yr Between -6 and -9 mm/yr Between -3 and -6 mm/yr Between 0 and -3 mm/yr Dry Season Source: Boer et al (2007)

11. Effects on the hydrological cycle • Precipitations • Evaporation • Soil moisture • Glaciers • Streamflow • Groundwater • Floods • Low flows • Water Demand

12. Base flows in rivers Ciliwung Barito Larona Source: Water R&D Center, Bandung (2007).

13. Perth inflows

14. Runoff from Finland:

15. Potential Impacts • All major socio-economic sectors will be affected, with a wide range of regional impacts: • Water • Ecosystems • Food • Coastal systems and low-lying areas • Industry, settlement and society • Health

16. Global warming will hit through water • Through climate change and the effects of e.g… • - changes in the hydrological cycle and water balance • - sea level rise • - increased water temperatures • Through increased climate variability in the form of more serious and frequent extremes, such as floods and droughts Source:TJK

17. Increasing number of hydrological extremes • Meuse river, December 1993 • Rhine river (secondary channel in floodplain), August 2003

18. Changes in major floods 1950-2000 There’s a consistent 50-year upward trend in every region except Oceania.

19. Flood damages are increasing

20. Relative Vulnerability of coastal deltas

21. Demographic Changes

22. Reasons for changes in flood risk and vulnerability Source: Kundzewicz & Schellnhuber, 2004

24. PROJECTIONS

25. 21st CenturyIs this going to be the flood century?(Too much water )

26. …or the drought century?

27. Probability distributions: temperatures (Adapted from Climate – Into the 21st Century, WMO, 2003, Cambridge University Press)

28. Hazards • Floods • Droughts • Flow regime changes

29. “Climate change: the hydrologic cycle” changes in variability (magnitude, severity, duration) changes in the averages/ trends

30. General Circulation Models (GCMs)to estimate future climate variables. Due to model uncertainty, an ensemble of models is more accurate than any single model. Temperature projections are much better than precipitation projections. Climate Impacts Group (2007) • AOGCMs • discretise the equations of fluid motion • parameterize processes at the subgrid scale. GCMs are constantly improving, and converging to observations. Reichler and Kim (2007) BAMS

31. Annual mean changes of precipitation, soil moisture, runoff and evaporation (2080-2099 relative to 1980-1999) Figure 10.12 SRES A1B scenario AR4 WGI Fig. 10.12

32. AR4 WGI Fig. 10.18 Changes in extremes 2080–2099 minus 1980–1999 for the A1B scenario annual total precipitation / number of wet days annual maximum number of consecutive dry days

33. Climate change on NZ east coast: Unirrigated drought risk, 2080s “Medium-high” scenario “Low-medium” scenario

34. Coastal floodingChange from the present day to the 2080s Unmitigated emissions Stabilisation at 750 ppm Stabilisation at 550 ppm

35. Change in annual runoff (%) –75 –50 –25 –5 to 5 25 50 75 Changes in river runoff from the present day to the 2080s Unmitigated emissions Stabilisation of CO2 at 750 ppm Stabilisation of CO2 at 550 ppm

36. Downscaling from Global to Basin Levels We must downscale GCM data to an appropriate resolution for hydrological predictions.

37. Resistance Strategies “Resistance” strategies focus mainly on the hazard (flood, drought, etc.) by aiming at prevention

38. Rainwater Harvesting:Reservoir in a building

39. DEMAND Management More efficient irrigation systems

40. Climate Alert System (CAS)Examples Seasonal climate forecast anomalies Climate monitoring Malaria monitoring at sentinel sites Year 1 Year 2 Year 3 Year 4 Climate Alert: low precip sets stage Climate Alert: high precip may trigger High precip; sentinels activated

41. Monthly, Seasonal, Interannual Monitoring

42. El Niño (1997) La Niña (1988) El Niño and La Niña

43. Regional Climate Outlook Forums GHACOF: Greater Horn of Africa COF SARCOF: Southern Africa COF PRESAO: Prévision Saisonnière en Afrique de l’Ouest PRESAC: Prévision Saisonnière en Afrique Centrale FOCRAII: Forum On regional Climate monitoring, assessment and prediction for Regional Association II (Asia) SSACOF: Southeast of South America COF WCSACOF: Western Coast of South America COF CCOF: Caribbean COF FCCA: Foro Regional del Clima de América Central PICOF: Pacific Islands COF SEECOF: SouthEastern Europe COF

44. Thank you

45. <0.04oC/year <0.04oC/year Between 0.04 and 0.07 oC/year Betweem 0.04 and 0.07 oC/year > 0.07 oC/year > 0.07 oC/year Maximum Temperature Minimum Temperature SOurce: Boer et al (2007)