What Climate Information Do Water Managers Need to Make Robust, Long-Term Plans?

1. What Climate Information Do Water Managers Need to Make Robust, Long-Term Plans? Robert Lempert Senior Scientist RAND US CLIVAR Mini-Symposium July 14, 2008

2. Climate Change Poses Significant Planning Challenge for Water Managers • Climate change will likely have large but uncertain impacts on supply and demand for water • “Stationarity is dead” • Most agencies already include climate (often implicitly) in many decisions • Amidst all the uncertainty one thing we do know for sure -- tomorrow’s climate will not be like the past’s • Relaxing this assumption poses key challenges • How do you adjust plans based on uncertain climate projections? • How do you communicate these plans, especially when uncertain long-term benefits require near-term costs?

3. Our Research Aims to Better Understand How to Characterize and Communicate Uncertain Information to Decision Makers • RAND Hosts NSF-Funded Center on Managing Climate Change Uncertainty • Conducts fundamental research to improve the design and effective use of computer-based decision support tools that enhance climate-related and other decisions under deep uncertainty • Research Focuses on Two Themes • Learn what characterizations of uncertainty are most effective for individuals and groups • Develop mathematical methods for scenario discovery and robust decisionmaking using • Applied to Two Policy Areas • Abrupt climate change • California water resources management

4. Outline • Climate vulnerability and response option analysis for Inland Empire Utilities Agency (IEUA) • What impacts may climate change have on IEUA’s current plans? • What should IEUA do in response? • Evaluating impacts of analysis on decision makers • Observations on needs for climate information

5. Conducted Vulnerability and Options Analysis for Inland Empire Utilities Agency (IEUA) • IEUA currently serves 800,000 people • May add 300,000 by 2025 • Water presents a significant challenge

6. Conducted Vulnerability and Options Analysis for Inland Empire Utilities Agency (IEUA) • IEUA currently serves 800,000 people • May add 300,000 by 2025 • Water presents a significant challenge • Current water sources include: • Groundwater 56% • Imports 32% • Recycled 1% • Surface 8% • Desalter 2%

7. Conducted Vulnerability and Options Analysis for Inland Empire Utilities Agency (IEUA) • IEUA currently serves 800,000 people • May add 300,000 by 2025 • Water presents a significant challenge • Current water sources include: • Groundwater 56% • Imports 32% • Recycled 1% • Surface 8% • Desalter 2% Focus of IEUA’s 20 year plan

8. Model projects future water supply and demand for IEUA service area Consistent with IEUA management plans and assumptions Reflect plausible trends of climate change We Built a Model to Assess Performance of IEUA Plans in Different Future States of World System data & climate forecasts IEUA Plans Model Performance of plans Based on WEAP software tool

9. Temperature Precipitation GCMs Project Plausible Temperature and Precipitation Ranges for Southern California • Derived from forecasts from 21 GCMs with A1B emissions scenario • Each forecast weighted by ability to reproduce past climate and level of agreement with other forecasts (Tebaldi et al.) % Change in Precipitation (2005 – 2030)

10. Generate Future Weather Sequences by Resampling Historic Local Climate Records KNN method produces hundreds of local weather sequences • Daily and monthly variability that matches historic Chino climate • Temperature and precipitation trends that match climate model forecasts (Yates et al.)

11. IEUA Plans Scenario A Plan generates surpluses in benign future climate Scenario B Plan suffers shortages in adverse future climate System data & climate forecasts 400 400 Shortage Dry-year yield 350 350 Surplus Surplus 300 300 Imports Imports 250 250 Annual supply (taf) Annual supply (taf) 200 200 Local Supplies Local Supplies 150 150 Groundwater Groundwater 100 100 50 50 Recycled Recycled 0 0 2005 2010 2015 2020 2025 2030 2005 2010 2015 2020 2025 2030 Year Year Temp: +0.7oC Precip: +3% Temp: +1.6oC Precip: -10% Model Assess Performance of IEUA Plans in Many Different Scenarios Performance of plans Model

12. Meet goals Slightly warmer & wetter climate Hotter & drier climate Don’t meet goals First Developed “Standard” Scenarios Based on Estimates of Key Driving Forces • Qualitatively choose the most important driving forces • Constructed “scenario matrix” based on these driving forces Scenario A Slightly warmer & wetterMeet all goals Scenario B Hotter & drier Meet all goals Scenario C Slightly warmer & wetter Miss goals Scenario D Hotter & drier Miss goals

13. These “Standard” Scenarios Suggest ThatClimate Change Could Significantly Affect IEUA • Meeting goals of 2005 UWMP could help manage risks Meet goals Scenario A Slightly warmer & wetterMeet all goals (0% of years) Scenario B Hotter & drier Meet all goals (19% of years) Slightly warmer & wetter climate Hotter & drier climate Scenario C Slightly warmer & wetter Miss goals (0% of years) Scenario D Hotter & drier Miss goals (42% of years) Don’t meet goals

14. Many Uncertain Factors Could Impact the Performance of Current IEUA Plan

15. No change Hotter Much drier Wetter Planners in S. California, for Instance, Face aRange of Possible Future Climate Conditions Summer-time temperature change (2000- 2030) Likelyrange +.1C 0 +2.1C Winter-time precipitation change (2000 - 2030) Likely range -19% +8% 0 Results based on statistical summary of 21 of the world’s best Global Climate Models

16. Many Uncertain Factors Could Impact the Performance of Current IEUA Plan

17. Meet Goals Miss Goals Conducted Elicitations Among IEUA’s Planners and Community to Estimate Likelihood of Achieving Goals Probability of meeting UWMP goals Recycling Replenishment Miss goal Goal Goal Miss goal

18. Many Uncertain Factors Could Impact the Performance of Current IEUA Plan

19. Assess alternatives for ameliorating vulnerabilities Candidate strategy Identify vulnerabilities Robust Decision Making (RDM) Enables Good Decisions Under Deep Uncertainty • Deep uncertainty obtains when • Decision makers don’t know or agree on the system model or the probability distributions for the inputs to the model • RDM is a quantitative decision analytic approach that • Identifies robust strategies, ones that work reasonably well compared to the alternatives across a wide range of plausible scenarios • RDM combines key advantages of scenario planning and quantitative decision analysis in ways that • Decision makers find credible • Contribute usefully to contentious debates

20. “Scenario Maps” Help Decision Makers Visualize How Plans Evolve Over Many Futures Current IEUA 2005 Urban Water Management Plan 4.0 PV supply cost ($ billions) 3.5 Scenario B • Adverse climate • $3.4 billion in supply cost • $1.9 billion in shortage cost Scenario A • Benign climate • $3.3 billion in supply cost • $0 in shortage cost 3.0 2.5 1.0 2.0 3.0 4.0 0 PV shortage cost ($ billions)

21. “Scenario Maps” Help Decision Makers Visualize How Plans Evolve Over Many Futures Current IEUA Plan 4.0 PV supply cost ($ billions) 3.5 3.0 (200 Scenarios) 2.5 1.0 2.0 3.0 4.0 0 PV shortage cost ($ billions)

22. “Scenario Maps” Help Decision Makers Visualize How Plans Evolve Over Many Futures Current IEUA Plan 4.0 Current plan generates high costs in 120 of 200 Scenarios PV supply cost ($ billions) 3.5 3.0 $3.75 billion cost threshold 2.5 1.0 2.0 3.0 4.0 0 PV shortage cost ($ billions)

23. Statistical Analysis Suggests Key Factors That Create Vulnerabilities for Existing Plan Current IEUA Plan 4.0 3.5 PV supply cost ($ billions) These three factors explain 70% of vulnerabilities of IEUA’s current plans 3.0 2.5 1.0 2.0 3.0 4.0 0 PV shortage cost ($ billions)

24. Response Options May Help IEUA Address These Vulnerabilities

25. Can Quantify Some, But Not All, Of These Costs Costs increase over time

26. In 2015, 2020, 2025, …. Monitor, and take additional action if supplies drop too low NO In 2015, 2020, 2025, …. Monitor, and take additional action if supplies drop too low Implement additional efficiency, recycling, and replenishment YES Should IEUA Act Now or Later to Reduce Potential Climate Vulnerabilities? Act now to augment 2005 Plan?

27. Compare Nine Strategies Over200 Scenarios Reflecting Key Uncertainties Current Plan forever Current Plan + DYY and recycling Current Plan + replenishment Current Plan with updates Current Plan + DYY and recycling with updates Current Plan + replenishment with updates Current Plan + efficiency Current Plan + efficiency with updates Static options Update options Current Plan + all enhancements 0 20 40 60 80 100 120 Number of Scenarios (PV Costs > $3.75 billion)

28. From 120 Down to 30 Static options Update options 0 20 40 60 80 100 120 Number of Scenarios (PV Costs > $3.75 billion) Just Allowing IEUA’s Current Plan to UpdateReduces Vulnerability Substantially Current Plan forever Current Plan + DYY and recycling Current Plan + replenishment Current Plan with updates Current Plan + DYY and recycling with updates Current Plan + replenishment with updates Current Plan + efficiency Current Plan + efficiency with updates Current Plan + all enhancements

29. Acting NowReduces Future Vulnerabilities Even More Current Plan with updates Current Plan + DYY and recycling with updates Current Plan + replenishment with updates Current Plan + efficiency Static options Update options Current Plan + efficiency with updates Current Plan + all enhancements 0 10 20 30 40 Number of Scenarios (PV Costs > $3.75 billion)

30. Implementation becomes more challenging Static options Update options 0 10 20 30 40 Number of Scenarios (PV Costs > $3.75 billion) Acting NowReduces Future Vulnerabilities Even More Current Plan with updates Current Plan + DYY and recycling with updates Current Plan + replenishment with updates Current Plan + efficiency Current Plan + efficiency with updates Current Plan + all enhancements This analysis helped IEUA decide to make more near-term efficiency investments, and to monitor performance and adapt as needed down the road

31. Outline • Climate vulnerability and response option analysis for Inland Empire Utilities Agency (IEUA) • Evaluating impacts of analysis on decision makers • Observations on needs for climate information

32. We Also Evaluated How This Analysis Affected Policy-Makers’ Views • Four IEUA workshops presented modeling results to participants including: • Agency professional managers and technical staff • Local elected officials • Community stakeholders • “Real-time” surveys measured participants’ • Understanding of concepts • Willingness to adjust policy choices based on information presented • Views on RDM

33. Surveys Suggest Workshop Changed Views Participants reported: • RDM helped support comparison of climate-related risks and choice among plans • Preference for scatter plot over histogram scenario displays After the workshop: • 35% said consequences of bad climate change now appeared “more serious” than before • 40% thought the likelihood of of bad climate change outcomes for the IEUA was “greater” than before • 75% though the ability of IEUA planner to plan for and manage effects was “greater” than before Overall, analysis increased: • Perceived likelihood of serious climate impacts • Confidence that IEUA could take effective actions to reduce its vulnerability to climate change • Support for near-term efficiency enhancements to current IEUA plan

34. Climate Information Re-Enforced IEUA’s Commitment to Implement 2005 Plan • Current climate projections adequate to: • Emphasize importance of UWMP long-range goals • Increase emphasis on conservation • Suggest importance of increased storm intensity • Climate change only one of several key uncertainties affecting performance of long-range plans • For many participants, willingness to accept seriousness of climate challenge contingent on confidence in effective response options

35. Other Water Agencies May Have Additional Information Needs • While IEUA’s favorable response options make it a special case, • Many water agencies likely to have sufficient information to their long-range plans more robust to climate change • Information needs often depend on vulnerabilities and available response options, but key needs include • Improved generation of future weather sequences • Length and frequency of future droughts • Characterization of potential extreme events

36. More Information David G. Groves, Robert J. Lempert, Debra Knopman, Sandra H. Berry: Preparing for an Uncertain Climate Future: Identifying Robust Water Management Strategies, RAND DB-550-NSF, 2008. David G. Groves, Debra Knopman, Robert J. Lempert, Sandra H. Berry, and Lynne Wainfan, Presenting Uncertainty About Climate Change to Water Resource Managers, RAND TR-505-NSF, 2007. David G Groves, David Yates, Claudia Tebaldi, “Developing and Applying Uncertain Global Climate Change Projections for Regional Water Management Planning,” submitted Robert J. Lempert, David G. Groves, Steven W. Popper, Steve C. Bankes: "A General, Analytic Method for Generating Robust Strategies and Narrative Scenarios,” Management Science, vol 52, no 4, April 2006 Steven W. Popper, Robert J. Lempert, and Steven C. Bankes: "Shaping the Future," Scientific American, vol 292, no. 4 pp. 66-71, April 2005 www.rand.org/ise/projects/improvingdecisions/

37. Thank you!

38. Statistical Analysis Suggests Key Driving Forces Generating High Cost Outcomes • Conducted statistical, cluster-finding analysis over all the model runs to identify the factors most strongly associated with shortages in UWMP Meet recycling goal Meet replenishment goal Future climate New conservation Reduced groundwater infiltration Climate on imports Miss Meet Exceed Miss Meet Exceed Drier Wetter -5% +20% -20% 0% Weak Strong Explains 70% of high cost cases

39. IEUA’s 2005 UWMP Calls for Significant Increase Conjunctive Use and Recycling