World Meteorological Organization Working together in weather, climate and water WMO: Climate and Water Departmentwww.wmo.int WMO 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 March, 2009, Istanbul, TURKEY Impacts of Climate Change on water related risks

Introduction

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 CO 2, CH 4, N 2 O, HFC S,…

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

OBSERVATIONS

Global mean temperatures   Warmest 12 years: 1998,2005,2003,2002,2004,2006, 2001,1997,1995,1999,1990,2000 Period Rate Years  /decade

Sea level in 20 th century Rates of sea level rise: mm yr -1, mm yr-1, 20 th Century mm yr -1, SPM-3b

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

Between 18 and 21 mm/yr Between 21 and 27 mm/yr Between 27 and 30 mm/yr Between 30 and 36 mm/yr 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 Wet Season Dry Season Source: Boer et al (2007)

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

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

Perth inflows

Runoff from Finland:

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

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 Global warming will hit through water Source:TJK

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

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

Flood damages are increasing

Relative Vulnerability of coastal deltas

Demographic Changes

(i) Changes in socio-economic systems Land-use change, increasing exposure and damage potential – floodplain development, growing wealth in flood-prone areas (ii) Changes in terrestrial systems Land-cover change - urbanization, deforestation, elimination of wetlands and floodplains, river regulation (iii) Changes in climate and atmospheric system Holding capacity of the atmosphere, intense precipitation, seasonality, circulation patterns Reasons for changes in flood risk and vulnerability Source: Kundzewicz & Schellnhuber, 2004

PROJECTIONS

21 st Century Is this going to be the flood century? (Too much water )

…or the drought century?

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

Hazards –Floods –Droughts –Flow regime changes

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

General Circulation Models (GCMs) to estimate future climate variables. GCMs are constantly improving, and converging to observations. Reichler and Kim (2007) BAMS AOGCMs discretise the equations of fluid motion parameterize processes at the subgrid scale. 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)

Figure AR4 WGI Fig Annual mean changes of precipitation, soil moisture, runoff and evaporation ( relative to ) SRES A1B scenario

AR4 WGI Fig 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

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

Coastal flooding Change from the present day to the 2080s Unmitigated emissions Stabilisation at 750 ppm Stabilisation at 550 ppm

99/ Hadley Center Changes in river runoff from the present day to the 2080s Unmitigated emissions Stabilisation of CO 2 at 750 ppm Stabilisation of CO 2 at 550 ppm –75–50–25–5 to Change in annual runoff (%)

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

Framework for Risk Management Framework for Risk Management Risk Transfer Risk Identification and Assessment Historical hazard data, analysis and changing hazard trends Exposed assets & vulnerability Risk quantification Sectoral planning Early warning systems Emergency preparedness & planning Catastrophe insurance/ bond markets Alternative risk transfer Risk Reduction (Prevention & Mitigation) Information and Knowledge Sharing Education and training Governance and Organizational Coordination and Cooperation

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

Rainwater Harvesting: Reservoir in a building

More efficient irrigation systems DEMAND Management

Flood Hazard Mapping Basin Planning Flood Proofing and Building Codes

Data CommunicationForecast Decision Support NotificationCoordinationActions Hydrological Observations Data transmissionFlood Forecasting Decisions Appropriate Individuals & Groups Preparedness, Response and Decisions Evacuation and Rescue operations a Critical Chain of Events and Actions Flood forecasting, warning and response system

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

Monthly, Seasonal, Interannual Monitoring

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

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

Thank you

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