Transcript What Climate Information Do Water Managers Need to

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
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?
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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
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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
4
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
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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%
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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
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We Built a Model to Assess Performance of
IEUA Plans in Different Future States of World
IEUA
Plans
System data &
climate forecasts
Model
Performance
of plans
– 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 tool
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GCMs Project Plausible Temperature and
Precipitation Ranges for Southern California
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.4
Temperature
6
4
3
.3
8
.2
2
1
.1
9
0
Probability Density
7
-1
.03
5
2
7
8
1
9
Precipitation
0
(Tebaldi et al.)
3
6
3
.02
Probability Density
– Each forecast weighted
by ability to reproduce
past climate and level of
agreement with other
forecasts
4
.01
– Derived from forecasts
from 21 GCMs with A1B
emissions scenario
0
1
2
Change in summer temperature (deg C) from 2000 - 2030
-30
-20
-10
0
10
Percent change in winter precipitation from 2000 - 2030
20
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Generate Future Weather Sequences by
Resampling Historic Local Climate Records
100 120
Historical
0
20 40 60 80
Drier
IEUA
1980
2000
2020
Year
2040
2060
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Temperature
Hotter
26
Warmer
Neutral
24
Temperature (dec C)
– Temperature and
precipitation trends that
match climate model
forecasts
(Yates et al.)
Neutral
Historical
22
– Daily and monthly variability
that matches historic Chino
climate
Wetter
20
Precipitation (cm)
KNN method produces
hundreds of local weather
sequences
Precipitation
IEUA
1980
2000
2020
Year
2040
2060
10
Model Assess Performance of IEUA Plans
in Many Different Scenarios
IEUA Plans
Performance
of plans
Model
System data & climate forecasts
Scenario B
Plan suffers shortages in
adverse future climate
400
400
350
350
Surplus
300
Imports
250
200
Local Supplies
150
Groundwater
100
50
0
2005
2015
2020
Year
2025
Temp: +0.7oC Precip: +3%
2030
Shortage
Dry-year yield
Surplus
300
Imports
250
200
Local Supplies
150
Groundwater
100
50
Recycled
2010
Annual supply (taf)
Annual supply (taf)
Scenario A
Plan generates surpluses in
benign future climate
0
2005
Recycled
2010
2015
2020
2025
2030
Year
Temp: +1.6oC Precip: -10%
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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
Meet goals
Scenario A
Slightly warmer
& wetter
Slightly Meet all goals
warmer &
wetter climate
Scenario B
Hotter & drier
Meet all goals
Scenario C
Scenario D
Slightly
warmer &
wetter
Miss goals
Hotter & drier
Miss goals
Hotter &
drier
climate
Don’t meet goals
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These “Standard” Scenarios Suggest That
Climate Change Could Significantly Affect IEUA
• Meeting goals of 2005 UWMP could help manage risks
Meet goals
Slightly
warmer &
wetter climate
Scenario A
Scenario B
Slightly warmer &
wetter
Meet all goals
(0% of years)
Hotter & drier
Meet all goals
(19% of years)
Scenario C
Scenario D
Slightly warmer
& wetter
Miss goals
(0% of years)
Hotter & drier
Miss goals
(42% of years)
Hotter &
drier
climate
Don’t meet goals
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Many Uncertain Factors Could Impact
the Performance of Current IEUA Plan
Natural
Processes
• Future temperatures
• Future precipitation
• Changes in groundwater processes
Performance of
Management
Strategies
Costs of Future
Supplies and
Management
Activities
• Development of aggressive waste-water
recycling program
• Implementation of groundwater
replenishment
• Imported supplies
• Water use efficiency
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Planners in S. California, for Instance, Face a
Range of Possible Future Climate Conditions
Summer-time temperature change
(2000- 2030)
No change
Hotter
Likely range
0
+.1C
+2.1C
Winter-time precipitation change
(2000 - 2030)
Much drier
Wetter
Likely range
-19%
0
+8%
Results based on statistical summary of 21 of the world’s best
Global Climate Models
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Many Uncertain Factors Could Impact
the Performance of Current IEUA Plan
Natural
Processes
• Future temperatures
• Future precipitation
• Changes in groundwater processes
Performance of
Management
Strategies
Costs of Future
Supplies and
Management
Activities
• Development of aggressive waste-water
recycling program
• Implementation of groundwater
replenishment
• Imported supplies
• Water use efficiency
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Conducted Elicitations Among IEUA’s
Planners and Community to Estimate
Likelihood of Achieving Goals
Probability of meeting UWMP goals
.04
Goal
Miss
goal
Goal
.01
.01
.02
Density
.02
.03
Miss
goal
0
0
Density
Replenishment
.03
Recycling
40
50
60
Recycling
70
80
80
90
100
110
120
130
GW
Meet Goals
Miss Goals
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Many Uncertain Factors Could Impact
the Performance of Current IEUA Plan
Natural
Processes
• Future temperatures
• Future precipitation
• Changes in groundwater processes
Performance of
Management
Strategies
Costs of Future
Supplies and
Management
Activities
• Development of aggressive waste-water
recycling program
• Implementation of groundwater
replenishment
• Imported supplies
• Water use efficiency
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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
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
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“Scenario Maps” Help Decision Makers
Visualize How Plans Evolve Over Many Futures
Current IEUA 2005 Urban Water Management Plan
4.0
PV supply 3.5
cost
($ billions)
Scenario B
Scenario A
3.0
•
Benign climate
•
$3.3 billion in supply
cost
•
$0 in shortage cost
•
Adverse climate
•
$3.4 billion in supply
cost
•
$1.9 billion in
shortage cost
2.5
0
1.0
2.0
3.0
4.0
PV shortage cost ($ billions)
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“Scenario Maps” Help Decision Makers
Visualize How Plans Evolve Over Many Futures
Current IEUA Plan
4.0
PV supply 3.5
cost
($ billions)
3.0
(200 Scenarios)
2.5
0
1.0
2.0
3.0
4.0
PV shortage cost ($ billions)
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“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 3.5
cost
($ billions)
3.0
$3.75 billion
cost threshold
2.5
0
1.0
2.0
3.0
4.0
PV shortage cost ($ billions)
22
Statistical Analysis Suggests Key Factors
That Create Vulnerabilities for Existing Plan
•
Natural
Processes
Future temperatures
• Future precipitation
• Changes in groundwater
processes
Current IEUA Plan
PV supply cost ($ billions)
4.0
• Development of aggressive
waste-water recycling program
Performance of
Management
Strategies
Costs of Future
Supplies and
Management
Activities
3.5
•
Implementation of groundwater
replenishment
•
Imported supplies
•
Water use efficiency
These three factors
explain 70% of
vulnerabilities of
IEUA’s current plans
3.0
2.5
0
1.0
2.0
3.0
PV shortage cost ($ billions)
4.0
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Response Options May Help IEUA
Address These Vulnerabilities
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Can Quantify Some, But Not All, Of These Costs
Average Cost
Shortages
Desalted Groundwater
Imported (Tier 2)
Imported Replenishment*
Imported (Tier 1)
Recycled Replenishment*
Groundwater
Stormwater Replenishment*
Recycled
Saved through efficiency
0
200
* includes the cost of spreading
400
600
800
1000
1200
Cost in 2005 ($/AF)
Costs increase over time
25
Should IEUA Act Now or Later to
Reduce Potential Climate Vulnerabilities?
In 2015, 2020, 2025, ….
NO
Monitor, and take
additional action
if supplies drop
too low
Act now to
augment
In 2015, 2020, 2025, ….
2005 Plan?
YES
Implement
additional
efficiency,
recycling, and
replenishment
Monitor, and take
additional action
if supplies drop
too low
26
Compare Nine Strategies Over
200 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)
27
Just Allowing IEUA’s Current Plan to Update
Reduces Vulnerability Substantially
Current Plan forever
Current Plan + DYY and recycling
From 120
Down to 30
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
Acting Now
Reduces 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)
29
Acting Now
Reduces 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
Implementation
becomes
more
challenging
Update options
Current Plan + efficiency with updates
Current Plan + all enhancements
0
10
20
30
40
Number of Scenarios
(PV Costs > $3.75 billion)
This analysis helped IEUA decide to make more near-term
efficiency investments, and to monitor performance and adapt
as needed down the road
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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
31
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
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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
33
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
34
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
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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/
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Thank you!
37
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
Miss
Meet
Exceed
Miss
Meet
Exceed
Meet replenishment goal
Future climate
Drier
Wetter
-5%
+20%
-20%
0%
Weak
Strong
New conservation
Reduced groundwater infiltration
Climate on imports
Explains 70% of high cost cases
38
IEUA’s 2005 UWMP Calls for Significant
Increase Conjunctive Use and Recycling
(TAF)
Urban Chino
Basin Ground
Water Use
Recycled Water
Supply
(direct use)
2005 Use
2010 Goal
2025 Goal
131
165
(+ 40%)
(+ 75%)
30
69
(+ 275%)
(+ 630%)
95
11
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