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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
• 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
– 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
7
– 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
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
9
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
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
10
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
12
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
16
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
17
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
18
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
19
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
20
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
• $0 in shortage cost
“Scenario Maps” Help Decision Makers Visualize How Plans Evolve Over Many Futures
“Scenario Maps” Help Decision Makers Visualize How Plans Evolve Over Many Futures
21
0 1.0 2.0 3.0 4.0PV shortage cost ($ 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
22
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
$3.75 billion cost threshold
Current plan generates high costs in 120 of 200 Scenarios
“Scenario Maps” Help Decision Makers Visualize How Plans Evolve Over Many Futures
“Scenario Maps” Help Decision Makers Visualize How Plans Evolve Over Many Futures
23
0 1.0 2.0 3.0 4.0PV shortage cost ($ 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
24
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
26
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
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
29
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)
30
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 road
31
OutlineOutline
• 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
• 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
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
33
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%)