what climate information do water managers need to make robust, long-term plans? robert lempert...

What Climate Information Do Water Managers Need

to Make Robust, Long-Term Plans?

What Climate Information Do Water Managers Need

to Make Robust, Long-Term Plans?

Robert LempertSenior Scientist

RAND

US CLIVAR Mini-SymposiumJuly 14, 2008

2

Climate Change Poses Significant Planning Challenge for Water Managers

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?

• 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

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

• 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

OutlineOutline

• 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


– What impacts may climate change have on IEUA’s current plans?

– What should IEUA do in response?



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

– Current water sources include:

• Groundwater 56%

• Imports 32%

• Recycled 1%

• Surface 8%

• Desalter 2%



• May add 300,000 by 2025


7

– Current water sources include:

• Groundwater 56%

• Imports 32%

• Recycled 1%

• Surface 8%

• Desalter 2%

Focus of IEUA’s 20 year plan



• May add 300,000 by 2025


8

Model

Performance of plans

IEUAPlans

System data &climate forecasts

We Built a Model to Assess Performance of IEUA Plans in Different Future States of World

We Built a Model to Assess Performance of IEUA Plans in Different Future States of World

– Model projects future water supply and demand for IEUA service area

• Consistent with IEUA management plans and assumptions

• Reflect plausible trends of climate change

– Model projects future water supply and demand for IEUA service area

• Consistent with IEUA management plans and assumptions

• Reflect plausible trends of climate change

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$

$

Based on WEAP software tool

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GCMs Project Plausible Temperature and Precipitation Ranges for Southern California

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

– 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.)

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8

7

6

54

3

2

1

0.1

.2.3

.4P

roba

bilit

y D

ens

ity

-1 0 1 2 3Change in summer temperature (deg C) from 2000 - 2030

Temperature

1

2

3

4 56

7

8

9

0.0

1.0

2.0

3P

roba

bilit

y D

ens

ity

-30 -20 -10 0 10 20Percent change in winter precipitation from 2000 - 2030

Precipitation

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Generate Future Weather Sequences by Resampling Historic Local Climate Records

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

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.)

020

4060

8010

012

0P

reci

pita

tion

(cm

)

1980 2000 2020 2040 2060Year

Wetter Neutral

Drier Historical

IEUA

Precipitation

2022

2426

28T

empe

ratu

re (

dec

C)

1980 2000 2020 2040 2060Year

Hotter

Warmer

Neutral

Historical

IEUA

Temperature

11

ModelPerformance

of plans

IEUA Plans

System data & climate forecasts

Model Assess Performance of IEUA Plans in Many Different Scenarios

Model Assess Performance of IEUA Plans in Many Different Scenarios

Temp: +1.6Temp: +1.6ooC Precip: -10%C Precip: -10%

Scenario BPlan suffers shortages in adverse future climate

00

5050

100100

150150

200200

250250

300300

350350

400400

20052005 20102010 20152015 20202020 20252025 20302030

YearYear

An

nu

al

su

pp

ly (

taf)

An

nu

al

su

pp

ly (

taf)

Recycled

GroundwaterGroundwater

Local SuppliesLocal Supplies

ImportsImports

Dry-year yieldDry-year yieldSurplusSurplus

ShortageShortage

Temp: +0.7Temp: +0.7ooC Precip: +3%C Precip: +3%

Scenario APlan generates surpluses in benign future climate

00

5050

100100

150150

200200

250250

300300

350350

400400

20052005 20102010 20152015 20202020 20252025 20302030

YearYear

An

nu

al

su

pp

ly (

taf)

An

nu

al

su

pp

ly (

taf)

RecycledRecycled

GroundwaterGroundwater

ImportsImports

SurplusSurplus

Local SuppliesLocal Supplies

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First Developed “Standard” Scenarios Based on Estimates of Key Driving Forces

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

Slightly warmer &

wetter climate

Hotter & drier climate

Meet goals

Don’t meet goals

Scenario ASlightly warmer

& wetterMeet all goals

Scenario CSlightly

warmer & wetter

Miss goals

Scenario BHotter & drier Meet all goals

Scenario DHotter & drier

Miss goals

13

These “Standard” Scenarios Suggest ThatClimate Change Could Significantly Affect IEUA

These “Standard” Scenarios Suggest ThatClimate Change Could Significantly Affect IEUA

• Meeting goals of 2005 UWMP could help manage risks

Slightly warmer &

wetter climate

Hotter & drier climate

Meet goals

Don’t meet goals

Scenario ASlightly warmer &

wetterMeet all goals(0% of years)

Scenario CSlightly warmer

& wetter Miss goals

(0% of years)

Scenario BHotter & drier Meet all goals(19% of years)

Scenario DHotter & drier

Miss goals(42% of years)

14

Many Uncertain Factors Could Impact the Performance of Current IEUA PlanMany Uncertain Factors Could Impact the Performance of Current IEUA Plan

Natural Processes

• Future temperatures

• Future precipitation

• Changes in groundwater processes

Performance of Management Strategies

• Development of aggressive waste-water recycling program

• Implementation of groundwater replenishment

Costs of Future Supplies and Management Activities

• Imported supplies

• Water use efficiency

15

Planners in S. California, for Instance, Face aRange of Possible Future Climate ConditionsPlanners in S. California, for Instance, Face aRange of Possible Future Climate Conditions

Summer-time temperature change(2000- 2030)

+.1C +2.1C0

Likely range

Results based on statistical summary of 21 of the world’s best Global Climate Models

Winter-time precipitation change (2000 - 2030)

+8%-19% 0

Likely range

No change Hotter

WetterMuch drier

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Natural Processes










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Conducted Elicitations Among IEUA’s Planners and Community to Estimate

Likelihood of Achieving Goals

Conducted Elicitations Among IEUA’s Planners and Community to Estimate

Likelihood of Achieving Goals

0.0

1.0

2.0

3.0

4D

ensi

ty

40 50 60 70 80Recycling

0.0

1.0

2.0

3D

ensi

ty

80 90 100 110 120 130GW

Recycling Replenishment

Goal GoalMissgoal

Missgoal

Probability of meeting UWMP goals

Meet Goals

Miss Goals

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Natural Processes










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Robust Decision Making (RDM) Enables Good Decisions Under Deep UncertaintyRobust 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

• 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

Candidate strategy

Identify vulnerabilities

Assess alternatives for ameliorating vulnerabilities

• RDM combines key advantages of scenario planning and quantitative decision analysis in ways that

– Decision makers find credible

– Contribute usefully to contentious debates

• RDM combines key advantages of scenario planning and quantitative decision analysis in ways that

– Decision makers find credible

– Contribute usefully to contentious debates

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0 1.0 2.0 3.0 4.0PV shortage cost ($ billions)

2.5

3.0

3.5

4.0

PV supply cost

($ billions) Scenario A

Scenario B

• Adverse climate

• $3.4 billion in supply cost

• $1.9 billion in shortage cost

Current IEUA 2005 Urban Water Management Plan

• Benign climate

• $3.3 billion in supply cost

• $0 in shortage cost

“Scenario Maps” Help Decision Makers Visualize How Plans Evolve Over Many Futures


21


2.5

3.0

3.5

4.0

PV supply cost

($ billions)

Current IEUA Plan

(200 Scenarios)



22


2.5

3.0

3.5

4.0

PV supply cost

($ billions)

Current IEUA Plan

$3.75 billion cost threshold

Current plan generates high costs in 120 of 200 Scenarios



23


2.5

3.0

3.5

4.0

PV

su

pp

ly c

ost

($

bil

lio

ns)

Current IEUA Plan

Statistical Analysis Suggests Key Factors That Create Vulnerabilities for Existing PlanStatistical Analysis Suggests Key Factors

That Create Vulnerabilities for Existing Plan

Natural Processes










These three factors explain 70% of vulnerabilities of IEUA’s current plans

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Response Options May Help IEUA Address These Vulnerabilities

Response Options May Help IEUA Address These Vulnerabilities

25

Can Quantify Some, But Not All, Of These CostsCan Quantify Some, But Not All, Of These Costs

Costs increase over time

Average Cost

0 200 400 600 800 1000 1200

Saved through efficiency

Recycled

Stormwater Replenishment*

Groundwater

Recycled Replenishment*

Imported (Tier 1)

Imported Replenishment*

Imported (Tier 2)

Desalted Groundwater

Shortages

Cost in 2005 ($/AF)* includes the cost of spreading

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Should IEUA Act Now or Later to Reduce Potential Climate Vulnerabilities?

Should IEUA Act Now or Later to Reduce Potential Climate Vulnerabilities?

Act now to Act now to augment augment

2005 Plan?2005 Plan?

NO

Monitor, and take Monitor, and take additional action additional action if supplies drop if supplies drop

too lowtoo low

In 2015, 2020, 2025, ….

YESImplement Implement additional additional efficiency, efficiency,

recycling, and recycling, and replenishmentreplenishment

In 2015, 2020, 2025, ….

Monitor, and take Monitor, and take additional action additional action if supplies drop if supplies drop

too lowtoo low

27

Compare Nine Strategies Over200 Scenarios Reflecting Key Uncertainties

Compare Nine Strategies Over200 Scenarios Reflecting Key Uncertainties

0 40 8060 100 12020

Static options

Update options

Number of Scenarios (PV Costs > $3.75 billion)

Current Plan forever

Current Plan + DYY and recycling

Current Plan + replenishment

Current Plan with updates

Current Plan + replenishment with updates

Current Plan + efficiency

Current Plan + efficiency with updates

Current Plan + DYY and recycling with updates

Current Plan + all enhancements

28

Just Allowing IEUA’s Current Plan to UpdateReduces Vulnerability Substantially

Just Allowing IEUA’s Current Plan to UpdateReduces Vulnerability Substantially

0 40 8060 100 12020

Static options

Update options

From 120Down to 30

Number of Scenarios (PV Costs > $3.75 billion)

Current Plan forever

Current Plan + DYY and recycling

Current Plan + replenishment







29

Acting NowReduces Future Vulnerabilities Even More








0 20 403010

Static options

Update options

Number of Scenarios(PV Costs > $3.75 billion)

30









0 20 403010

Static options

Update options

Number of Scenarios(PV Costs > $3.75 billion)

Implementation becomes

more challenging

This analysis helped IEUA decide to make more near-term efficiency investments, and to monitor performance and adapt

as needed down the road

31

OutlineOutline







32

We Also Evaluated How This Analysis Affected Policy-Makers’ Views

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

• 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

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Surveys Suggest Workshop Changed ViewsSurveys 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

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

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

• 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

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

• 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 InformationMore 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/

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

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

• 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 ExceedMeet

Miss ExceedMeet

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 RecyclingIEUA’s 2005 UWMP Calls for Significant Increase Conjunctive Use and Recycling

(TAF) 2005 Use 2010 Goal 2025 Goal

Urban Chino Basin Ground

Water Use95

131

(+ 40%)

165

(+ 75%)

Recycled Water Supply

(direct use)

1130

(+ 275%)

69

(+ 630%)

what climate information do water managers need to make robust, long-term plans? robert lempert...

Documents

climate information

past climate

tomorrows climate

uncertain climate projections

water managersclimate

options analysis

ieua management plans

impacts of analysis