Transcript ppt
Background & Motivation: What does Climate have to offer? Water and CRM Technical Workshop and Training Addis Ababa, June 30 – July 2, 2009 Credits: IRI, Upmanu Lall, Casey Brown, Dave Watkins “Fierce for fresh water+/maytensions: well become 260competition international basins: a source of conflict in the future.” longstanding, always,& wars growing with demand Kofi Annan, March 2001 Source: Grey & Sadoff, World Bank Semi-Arid and Arid Sub-Tropics and Tropics & Areas w/ High Population Density In the 20th century the world population tripled – while water use multiplied six-fold! By 2025 two thirds of the people in the world are expected to live in areas of water shortage or stress. Source: Vorosmarty et al 2000 Climate change or just people? Source: Vorosmarty et al 2000 Pop + Consumption= Demand 54% of annual available fresh water is currently being used world-wide • • Assuming current consumption, 70% will be used due to population growth alone by 2025. For developed country per capita consumption 90% will be used by 2025. • Water Availability 1.7 x decrease 4.5 x decrease 7.5 x decrease Shiklomanov Annual Variability of Rainfall Economic Impact of Climate Variability Ethiopia: Rainfall, GDP and Agric. GDP 80 25 20 60 40 10 20 5 0 rainfall variation around the mean -80 GDP growth Ag GDP growth year World Bank Source: World Bank 2005 2000 -5 -10 -15 -40 -60 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985 1984 -20 1983 0 1982 percentage 15 -20 -25 -30 Development Trajectories in River Basins Development Utilization Allocation The Message An imminent freshwater crisis • Demand > Supply • Access to safe drinking water: currently poor • High variability in supply Major investments needed for growth • Potential for trans-boundary conflict • Climate Change: Cause or Effect? Water is the major uncertainty The Challenge • Social and institutional factors often dictate resource management strategies • Climate is a major determinant of risk • As understanding of climate improves, how can we adapt traditional management strategies to use this new information to reduce societal risk and improve system resilience ? • How do we balance the needs of a local resource manager with products that convey large scale, technical and yet uncertain information ? • How do we judge failure or success ? The Motivation • Adaptation to climate change for water resources will require a change from a business as usual approach • The climate is no longer stationary with increasing climate variability and changing normals • The temporal structure to variability is not static • Risk varies different needs • New climate science is needed for water resource managers Managing Water Resource Systems • Balance Water Supply and Demand • Historical rules for resource allocation Climate Water • How much, and when should these rules be modified ? Agriculture Energy Health • How do we assess and communicate potential impacts of action & inaction ? Human Activity Dam 1 Electric Grid Dam 2 Irrigated Farms Well Field Irrigated Farms Dam 3 New City Muddy River The Question What can Water Resource Managers do? Climate Risk Management (CRM) Climate Risk Management One definition: “CRM focuses on pressing issues of here and now while factoring in projected changes” (WB) Protecting against climate hazards so climate opportunities can be utilized Methodology to increase decision-making as a major pathway to adaptation for climate change by leveraging climate science Key Issues How should climate change be addressed? • It’s an open research question • Much can be gained by learning from those actively engaging the concept of nonstationarity of climate in practice. Case studies a key start. Recommend a technical assessment with weaknesses exposed. • Understanding of climate impacts on water systems is the starting point • Historical data remains the most important source of climate information for any water system • Solutions/adaptations should be identified, evaluated and implemented via IWRM approach Integrating Management of Climate Risks An operational definition: 1. Identify hazards associated with climate risks (of all time scales) to the water system 2. Characterize the climate risks 3. Propose/Assess portfolio of solutions/adaptations to key climate (and other) risks Integrating Management of Climate Risks 1. Identify hazards associated with climate risk to the water system • What are the key climate challenges that the system faces now (e.g., frequent drought, flood events, variable flows) • What damages occur as functions of these events? • Where are the impacts felt? Are there distributional effects? Is the environment considered/protected? • Are there opportunity losses due to risk aversion associated with current climate risks? Integrating Management of Climate Risks 2. Characterize hydroclimatic risk • What are the probabilities, recurrence periods, etc. of hazard causing events • Is there spatial or temporal structure? • Are there probable/predictable changes expected? • What are the most plausible future scenarios and the uncertainty associated with them? • How do these risks compare to the social, economic, demographic and environmental challenges the water system faces (severity, uncertainty)? Integrating Management of Climate Risks 3. Propose/Assess portfolio of solutions/adaptations to Climate Risks • Incorporate uncertainty of climate futures in the decision process • May favor flexibility over structure (soft vs hard approaches) • Solutions have spatial and temporal characteristics that modulate appropriateness based on the climate risks • Risk solutions are dependent on timeframe of analysis: - Operational – fixed infrastructure, certain sunk costs - Planning – infrastructure and other system decisions Application Move from Static to Dynamic Risk Management • Changing climate • Changing goals • Changing population demographics and landscape “Hard” and “Soft” Technologies • Design & Operation of Structures • Allocation Rules and Water Rights • Risk Sharing and Reduction Strategies Develop ideas through examples at multiple scales Application Design flexible, adaptable systems – reliability no longer assured Suite of options: • Infrastructure: important, but effective range likely exceeded • Economic instruments: water banks, options, contracts • Seasonal forecasts • Flexible operating rules • Insurance • Characterize uncertainties / probabilities Redundancy in the system Continuous system performance Good results payoff in long run Application Can we leverage applications of climate science to reduce (exploit) negative (positive) impacts of climate variability? Application - Forecasts Reservoirs operated without forecasts in risk averse mode • Anticipating drought of record in every year • Water is kept in the reservoir as a reserve for a drought, instead of being delivered to irrigators or being used for hydroelectricity production Forecasts provide enhanced estimate of drought risk • Identifying opportunities in years when drought risk is low (eg La Niña) Source: C. Brown (IRI) Application - Forecasts Historical Inflow Observations Sea Surface Temperatures Photo: MWSS Global Climate Model Cross-Validated Model RAINFALL WINDS Statistical Model Forecast Inflow for OND 2002 Source: B. Lyon Application - Forecasts Probability of exceeding a seasonal rainfall threshold Choose parameter, quantity (i.e., number of dry spells of 7 or more days), and statistic of interest (i.e. probability of exceedance) Application - Health Suitability for Malaria Transmission Application - Agriculture Index Insurance for Crops Bridging Climate into Risk Management Summarizing Climate into Risk Management PDF/CDF “prob. of exceedance” relevant variables: eg: reservoir inflow dry spell or flood risk * historical * predictive * real-time monitoring = tailored probabilistic climate information within a specific institutional and policy setting