decision making under deep uncertainty robert lempert director rand pardee center for longer range...
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Decision Making Under Deep UncertaintyDecision Making Under Deep Uncertainty
Robert LempertDirector
RAND Pardee Center for Longer Range Global Policy and the Future Human Condition
July 8, 2009
2
Traditional Planning Methods Can Illuminate Trees Rather Than ForestTraditional Planning Methods Can
Illuminate Trees Rather Than Forest
Traditional analytic methods characterize uncertainties as a prelude to assessing alternative decisions
Traditional analytic methods characterize uncertainties as a prelude to assessing alternative decisions
Predict Act
Climate change confronts decisionmakers with deep uncertainty, where
– They do not know, and/or key parties to the decision do not agree on, the system model, prior probabilities, and/or “cost” function
Decisions can go awry if decisionmakers assume risks are well-characterized when they are not
– Uncertainties are underestimated
– Competing analyses can contribute to gridlock
– Misplaced concreteness can blind decision-makers to surprise
Climate change confronts decisionmakers with deep uncertainty, where
– They do not know, and/or key parties to the decision do not agree on, the system model, prior probabilities, and/or “cost” function
Decisions can go awry if decisionmakers assume risks are well-characterized when they are not
– Uncertainties are underestimated
– Competing analyses can contribute to gridlock
– Misplaced concreteness can blind decision-makers to surprise
3
Forecasting the Unpredictable Can Contribute to Bad Decisions
Forecasting the Unpredictable Can Contribute to Bad Decisions
Gross national product (trillions of 1958 dollars)
2.22.0
1.81.6
1.4
1.2
1.0.8
.6
.4
.2
0180
Energy use (1015 Btu per year)
0
Historical trend
continued1970
1920 19291940
19501960
1910
1973
19731900
1890
20 40 60 80 100 120 140 160
1975 Scenarios• In the early 1970s forecasters made projections of U.S energy use based on a century of data
• In the early 1970s forecasters made projections of U.S energy use based on a century of data
4
Forecasting the Unpredictable Can Contribute to Bad Decisions
Forecasting the Unpredictable Can Contribute to Bad Decisions
Gross national product (trillions of 1958 dollars)
2.22.0
1.81.6
1.4
1.2
1.0.8
.6
.4
.2
0180
Energy use (1015 Btu per year)
0
Historical trend
continued1970
1920 19291940
19501960
1910
1973
19731900
1890
20 40 60 80 100 120 140 160
2000 Actual
1990
19801977
1975 Scenarios2000 Actual
1990
19801977
• In the early 1970s forecasters made projections of U.S energy use based on a century of data
… they all were wrong
• In the early 1970s forecasters made projections of U.S energy use based on a century of data
… they all were wrong
5
OutlineOutline
• Robust Decision Making (RDM)
• Climate vulnerability and response option analysis for Inland Empire Utilities Agency (IEUA)
• Observations
• Robust Decision Making (RDM)
• Climate vulnerability and response option analysis for Inland Empire Utilities Agency (IEUA)
• Observations
6
New Technology Allows Computer to Serve As “Prosthesis for the Imagination”
New Technology Allows Computer to Serve As “Prosthesis for the Imagination”
• Robust Decision Making (RDM) is a quantitative decision analytic approach that
– Characterizes uncertainty with multiple, rather than single, views of the future
– Evaluates alternative decision options with a robustness, rather than optimality, criterion
– Iteratively identifies vulnerabilities of plans and evaluates potential responses
• Robust Decision Making (RDM) is a quantitative decision analytic approach that
– Characterizes uncertainty with multiple, rather than single, views of the future
– Evaluates alternative decision options with a robustness, rather than optimality, criterion
– Iteratively identifies vulnerabilities of plans and evaluates potential responses
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
7
RDM Has Effectively Addressed Many Types of Decisions Under Deep Uncertainty
RDM Has Effectively Addressed Many Types of Decisions Under Deep Uncertainty
Energy, Environment, and Climate Change
• Long-Range Natural Resource Management
• Renewable portfolios standards
• Center on climate change decision making
National Security
• Terrorism Insurance
• Force procurement and deployment
• Pre-conflict shaping strategies
Commercial-Sector Applications
• Electric utilities’ strategies under deregulation
• Product and technology planning in the auto industry
8
Compare Alternative Approaches to Managing Catastrophic Event with Unknown ProbabilityCompare Alternative Approaches to Managing Catastrophic Event with Unknown Probability
• Consider town on shore of pristine lake
– Lake can switch abruptly to undesirable and potentially irreversible eutrophic state at unknown pollution concentration
• Citizens must decide how much pollution to emit
– Gain small utility from emitting pollution to lake and lose significant utility if lake goes eutrophic
– Deeply uncertain about location of concentration threshold
• Alternative decision approaches include:
– Optimum expected utility
– Precautionary principle
– Robust decision making
• Consider town on shore of pristine lake
– Lake can switch abruptly to undesirable and potentially irreversible eutrophic state at unknown pollution concentration
• Citizens must decide how much pollution to emit
– Gain small utility from emitting pollution to lake and lose significant utility if lake goes eutrophic
– Deeply uncertain about location of concentration threshold
• Alternative decision approaches include:
– Optimum expected utility
– Precautionary principle
– Robust decision making
Robert J. Lempert and Myles T. Collins., 2007: “Managing the Risk of Uncertain Threshold Response: Comparison of Robust, Optimum, and Precautionary Approaches” Risk Analysis 27 (4), 1009–1026
9
Use Simple Simulation Model of Lake System to Assess Consequences of Town’s Decisions
Use Simple Simulation Model of Lake System to Assess Consequences of Town’s Decisions
•Three “policy levers” describe town’s citizens’ adaptive strategy
– Initial pollution emissions (L0)
– Maximum yearly increase in emissions (L)
– Safety margin (S) – buffer between pollution emissions and estimate of critical threshold (Xcrit)
•Over time, citizens learn true value of critical threshold– Observations increasingly accurate as level of pollution approaches unknown
threshold
Nutrients in LakeNatural Emissions
Nutrient sink
Recycling when eutrophicLt = f(L0,L,S)
AnthropogenicEmissions
Learning
€
Lt = f L0,ΔL,S( )
Lempert and Collins (2007)
10
Well Characterized Uncertainty Suggests An Optimal Strategy
Well Characterized Uncertainty Suggests An Optimal Strategy
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.3 0.4 0.5 0.6 0.7 0.8 0.9
Xcrit
Probability Density
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.3 0.4 0.5 0.6 0.7 0.8 0.9
Xcrit
Probability Density
Optimal Strategy w Uncertainty
Linit 0.37
Safety Margin 3.0
L 0.11
Mean PVU 13.
Probability distribution
for critical threshold
Xcrit
Lempert and Collins (2007)
11
Robust Strategies Trade Some Optimal Performance for Less Sensitivity to Assumptions
Robust Strategies Trade Some Optimal Performance for Less Sensitivity to Assumptions
• Represent uncertainty about critical threshold with set of multiple, plausible distributions
• Define expected regret of strategy s contingent on distribution i
where strategy s regret is
• Compared to optimal strategy, a robust strategy has small weighted average of best and worst expected regret
• Represent uncertainty about critical threshold with set of multiple, plausible distributions
• Define expected regret of strategy s contingent on distribution i
where strategy s regret is
• Compared to optimal strategy, a robust strategy has small weighted average of best and worst expected regret
€
ρi X( )
€
R s,i = Rs x( )ρ i x( )dxx
∫
€
Rs x( )=Maxs'pvU s' x( )[ ]− pvU s x( )
€
Vs = zR s,best + 1− z( )R s,worst
€
0 ≤ z <1
Lempert and Collins (2007)
12
Find Vulnerabilities of Optimal StrategyFind Vulnerabilities of Optimal Strategy
Regret of Strategy A over different values of Xcrit
0
5
10
15
20
25
30
0.3 0.4 0.5 0.6 0.7 0.8 0.9
Xcrit
Regret of Strategy A
30773
Vulnerabilities
Present value utility of optimum strategy
Lempert and Collins (2007)
13
Compare Regret Over Range of FuturesCompare Regret Over Range of Futures
A
B
C
D
E
F
G
0
1
2
3
4
5
6
7
8
9
0 20 40 60 80 100 120 140
Expected Regret over Strategy A's Vulnerable Futures (z=0)
Expected Regret over Initial Priors (z=1)A
B
C
D
E
F
G
0
1
2
3
4
5
6
7
8
9
0 20 40 60 80 100 120 140
Expected Regret over Strategy A's Vulnerable Futures (z=0)
Expected Regret over Initial Priors (z=1)
Optimal Strategy
Lempert and Collins (2007)
14
Town’s Citizens Have More Robust Options Than Strategy A
Town’s Citizens Have More Robust Options Than Strategy A
0
2
4
6
8
10
12
14
16
18
20
0.01 0.1 1 10 100
Odds of Strategy A Priors
Expected Regret
A
BC
D
E
G
F
0
2
4
6
8
10
12
14
16
18
20
0.01 0.1 1 10 100
Odds of Strategy A Priors
Expected Regret
A
BC
D
E
G
F
Optimal Strategy
PotentialRobust Strategy
Lempert and Collins (2007)
15
OutlineOutline
• Robust Decision Making (RDM)
• 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?
• Observations
• Robust Decision Making (RDM)
• 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?
• Observations
16
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?
17
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
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.
18
– Current water sources include:
• Groundwater 56%
• Imports 32%
• Recycled 1%
• Surface 8%
• Desalter 2%
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
Groves et. al. (2007)
19
– Current water sources include:
• Groundwater 56%
• Imports 32%
• Recycled 1%
• Surface 8%
• Desalter 2%
Focus of IEUA’s 20 year plan
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
Groves et. al. (2007)
20
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
#
#
%
##
##
#
#
`
%
#
#
# #
#
#
#
#
`
#
#
##
#
#%
##
`
# #
%
$
$
Based on WEAP software toolGroves et. al. (2007)
21
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.)
9
8
7
6
54
3
2
1
-1 0 1 2 3Change in summer temperature (deg C) from 2000 - 2030
Temperature
1
2
3
4 56
7
8
9
-30 -20 -10 0 10 20Percent change in winter precipitation from 2000 - 2030
Precipitation
Groves et. al. (2007)
22
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.)
1980 2000 2020 2040 2060Year
Wetter Neutral
Drier Historical
IEUA
Precipitation
1980 2000 2020 2040 2060Year
Hotter
Warmer
Neutral
Historical
IEUA
Temperature
Groves et. al. (2007)
23
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
Groves et. al. (2007)
24
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
Groves et. al. (2007)
25
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
Groves et. al. (2007)
26
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
Groves et. al. (2007)
27
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
• $0 in shortage cost
“Scenario Maps” Help Decision Makers Visualize How Plans Evolve Over Many Futures
“Scenario Maps” Help Decision Makers Visualize How Plans Evolve Over Many Futures
David G. Groves, Robert J. Lempert, Debra Knopman, Sandra H. Berry: Preparing for an Uncertain Climate Future: Identifying Robust Water Management Strategies, RAND DB-550-NSF, 2008.
28
0 1.0 2.0 3.0 4.0PV shortage cost ($ billions)
2.5
3.0
3.5
4.0
PV supply cost
($ billions)
Current IEUA Plan
(200 Scenarios)
“Scenario Maps” Help Decision Makers Visualize How Plans Evolve Over Many Futures
“Scenario Maps” Help Decision Makers Visualize How Plans Evolve Over Many Futures
Groves et. al. (2008)
29
0 1.0 2.0 3.0 4.0PV shortage cost ($ billions)
2.5
3.0
3.5
4.0
PV supply cost
($ billions)
Current IEUA Plan
$3.75 billion cost threshold
Current plan generates high costs in 120 of 200 Scenarios
“Scenario Maps” Help Decision Makers Visualize How Plans Evolve Over Many Futures
“Scenario Maps” Help Decision Makers Visualize How Plans Evolve Over Many Futures
Groves et. al. (2008)
30
Discover Key Scenarios in Ensembles of Many Model Runs
Discover Key Scenarios in Ensembles of Many Model Runs
1. Ran the model 200 times under different combinations of uncertain factors (e.g. temperature and precipitation trends and others)
2. Used statistical algorithms to identify conditions that lead to 2005 UWMP to perform poorly
3. These factors become key driving forces for “policy-relevant” scenarios
1. Ran the model 200 times under different combinations of uncertain factors (e.g. temperature and precipitation trends and others)
2. Used statistical algorithms to identify conditions that lead to 2005 UWMP to perform poorly
3. These factors become key driving forces for “policy-relevant” scenarios
0
10
20
30
40
50
60
70
80
Number of futures
2.5 3 3.5 4 4.5 5 5.5 6 6.5
NPV total costs ($ billions)
UWMP Forever
Nu
mb
er o
f ru
ns
High Cost(120 runs)
Statistical analysis suggests factors that
contribute most to these undesirable
outcomes
Groves et. al. (2007)
31
0 1.0 2.0 3.0 4.0PV shortage cost ($ billions)
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
• 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
These three factors explain 70% of vulnerabilities of IEUA’s current plans
Groves et. al. (2008)
32
Response Options May Help IEUA Address These Vulnerabilities
Response Options May Help IEUA Address These Vulnerabilities
Groves et. al. (2008)
33
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
Groves et. al. (2008)
34
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
Groves et. al. (2008)
35
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
Groves et. al. (2008)
36
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
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
Groves et. al. (2008)
37
Acting NowReduces Future Vulnerabilities Even More
Acting NowReduces Future Vulnerabilities Even More
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
0 20 403010
Static options
Update options
Number of Scenarios(PV Costs > $3.75 billion)
Groves et. al. (2008)
38
Acting NowReduces Future Vulnerabilities Even More
Acting NowReduces Future Vulnerabilities Even More
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
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 roadGroves et. al. (2008)
39
OutlineOutline
• Robust Decision Making (RDM)
• Climate vulnerability and response option analysis for Inland Empire Utilities Agency (IEUA)
• Observations
• Robust Decision Making (RDM)
• Climate vulnerability and response option analysis for Inland Empire Utilities Agency (IEUA)
• Observations
40
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
.01
.02
.03
.04
Density
40 50 60 70 80Recycling
0
.01
.02
.03
Density
80 90 100 110 120 130GW
Recycling Replenishment
Goal GoalMissgoal
Missgoal
Probability of meeting UWMP goals
Meet Goals
Miss Goals Groves et. al. (2007)
41
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
Groves et. al. (2007)
42
Meet recycling goal
Meet replenishment goal
Future climate
New conservation
Percolation decrease
Climate on imports
Miss ExceedMeet
Miss ExceedMeet
Drier Wetter
-5% +20%
-20% 0%
Weak Strong
Explains 70% of high cost cases
Analysis Suggests Factors That Cause Severe Shortages for IEUA’s 20 Year Plan
Analysis Suggests Factors That Cause Severe Shortages for IEUA’s 20 Year Plan
Climate-related uncertainties facing IEUA Climate-related uncertainties facing IEUA
Groves et. al. (2007)
43
RDM Enables Effective Planning Based on Multiple Views of FutureRDM Enables Effective Planning
Based on Multiple Views of Future
• Use many scenarios to imagine the future
– Not a single forecast
• Seek robust strategies that do well across many scenarios assessed according to several values
– Not optimal strategies
• Employ strategies that evolve over time in response to changing conditions
– Not "fixed" strategies
• Use computer as “prosthesis for the imagination”
– Not a calculator
• Use many scenarios to imagine the future
– Not a single forecast
• Seek robust strategies that do well across many scenarios assessed according to several values
– Not optimal strategies
• Employ strategies that evolve over time in response to changing conditions
– Not "fixed" strategies
• Use computer as “prosthesis for the imagination”
– Not a calculator
44
More InformationMore InformationDavid 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.
Groves, David G, David Yates, Claudia Tebaldi, 2008: “Developing and Applying Uncertain Global Climate Change Projections for Regional Water Management Planning,” Water Resources Research, 44(12): W12413
Robert J. Lempert and Myles T. Collins., 2007: “Managing the Risk of Uncertain Threshold Response: Comparison of Robust, Optimum, and Precautionary Approaches” Risk Analysis 27 (4), 1009–1026
David G. Groves and Robert J. Lempert, 2007: A new analytic method for finding policy-relevant scenarios, Global Environmental Change 17, 73-85.
Robert J. Lempert, Steven W. Popper, Steven C. Bankes, 2003: Shaping the Next One Hundred Years: New Methods for Quantitative, Long-Term Policy Analysis, RAND MR-1626-RPC, Aug.
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.
Groves, David G, David Yates, Claudia Tebaldi, 2008: “Developing and Applying Uncertain Global Climate Change Projections for Regional Water Management Planning,” Water Resources Research, 44(12): W12413
Robert J. Lempert and Myles T. Collins., 2007: “Managing the Risk of Uncertain Threshold Response: Comparison of Robust, Optimum, and Precautionary Approaches” Risk Analysis 27 (4), 1009–1026
David G. Groves and Robert J. Lempert, 2007: A new analytic method for finding policy-relevant scenarios, Global Environmental Change 17, 73-85.
Robert J. Lempert, Steven W. Popper, Steven C. Bankes, 2003: Shaping the Next One Hundred Years: New Methods for Quantitative, Long-Term Policy Analysis, RAND MR-1626-RPC, Aug.
www.rand.org/ise/projects/improvingdecisions/
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Thank you!
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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
Groves et. al. (2007)
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First Three Workshops Compared Alternative Approaches to Uncertainty
First Three Workshops Compared Alternative Approaches to Uncertainty
Workshop design approximates on-going laboratory experiments
Compared three approaches
• Traditional qualitative scenarios
• Probabilistic forecasts
• RDM with Scenario discovery
Groves et. al. (2007)
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RDM Scenarios More Useful, But More Difficult to Understand
RDM Scenarios More Useful, But More Difficult to Understand
Questionnaire item Traditional Scenarios
Scenario Discovery
Provides results that can be used in planning
Agree somewhat
Agree strongly
Provides information on how to improve plan
Agree somewhat
Agree somewhat
Is easy to explain to decisionmakers
Agree somewhat
Disagree strongly
• Traditional scenarios – Gave IEUA much of the information they needed
– Emphasized the importance of achieving goals in IEUA’s plan
• Scenario Discovery – Provided more useful information
– Sparked discussion of adaptive strategies
• Traditional scenarios – Gave IEUA much of the information they needed
– Emphasized the importance of achieving goals in IEUA’s plan
• Scenario Discovery – Provided more useful information
– Sparked discussion of adaptive strategies
Groves et. al. (2007)
49
RDM Scenarios More Useful, But More Difficult to Understand
RDM Scenarios More Useful, But More Difficult to Understand
Questionnaire item Traditional Scenarios
Scenario Discovery
Provides results that can be used in planning
Agree somewhat
Agree strongly
Provides information on how to improve plan
Agree somewhat
Agree somewhat
Is easy to explain to decisionmakers
Agree somewhat
Disagree strongly
• Traditional scenarios – Gave IEUA much of the information they needed
– Emphasized the importance of achieving goals in IEUA’s plan
• Scenario Discovery – Provided more useful information
– Sparked discussion of adaptive strategies
• Traditional scenarios – Gave IEUA much of the information they needed
– Emphasized the importance of achieving goals in IEUA’s plan
• Scenario Discovery – Provided more useful information
– Sparked discussion of adaptive strategies
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Fourth (Adaptive Strategy) Workshop Compared Different Presentations of RDM
Fourth (Adaptive Strategy) Workshop Compared Different Presentations of RDM
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 planners 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 planners 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 planGroves et. al. (2008)
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ObservationsObservations• Analysis suggests IEUA’s current long-range plans:
– Vulnerable to climate change
– Can be made more resilient by near-term conservation, attention to storm intensity, and effective future monitoring and updating
• Measurements suggest
– RDM analysis effectively shifted views on seriousness of climate challenges and appropriate responses, but requires more work to be easily understood by policy-makers
– Importance of linking effective response options with presentation of climate uncertainty
• Currently using this approach to help several major water agencies include climate in their long-range plans
• Analysis suggests IEUA’s current long-range plans:
– Vulnerable to climate change
– Can be made more resilient by near-term conservation, attention to storm intensity, and effective future monitoring and updating
• Measurements suggest
– RDM analysis effectively shifted views on seriousness of climate challenges and appropriate responses, but requires more work to be easily understood by policy-makers
– Importance of linking effective response options with presentation of climate uncertainty
• Currently using this approach to help several major water agencies include climate in their long-range plans