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Climate and Water
Can the water sector do anything with the
inherently uncertain climate change scenarios ? Prof. Dr. Pavel Kabat
Wageningen University and Research Center, NetherlandsEarth System Science & Climate Change Group www.ess.wur.nlClimate Centre (CCB) Wageningen UR www.wur.nl/ccb National Climate Change and Spatial Planning Research Programme of Netherlands www.climatechangesspatialplanning.nl
With thanks to:Prof. Mike Hulmes, Tyndall Centre, UKProf. Peter Cox, Exeter University & Hadley Centre, UKProf. Joseph Alcamo, Kassel University & UNEPProf. Kundzewich & IPCC 4AR colleagues
Worldwide Water Use by Region in km3 per year
0
500
1000
1500
2000
2500
3000
3500
1900 1920 1940 1960 1980 2000 2020
EuropeNorth AmericaAfricaAsiaSouth AmericaAustralia& Pacific
0
1000
2000
3000
4000
5000
6000
1900 1920 1940 1960 1980 2000 2020
Wa
ter
Use
in
km
^3
pe
r ye
ar
AgricultureIndustryHouseholdsReservoiresTotal
Worldwide Water Use by Sector
The current situation
1 billion people without access to safe drinking water
1.4 billion people in watersheds with < 1000m3/capita/year
2.4 billion people with poor sanitation
IPCC 2007
ALL WATER RELATED (WATER DEPENDENT)
SECTORS
Climate scenarios chain………..
Emissions
Narratives
Concentrations
Climate changeImpacts
So What are the Limits to Climate Prediction?
Uncertainties in climate prediction arise from:
Lack of knowledge (Epistemic uncertainty)
Parameter uncertainty
Structural uncertainty
Randomness (Natural stochastic uncertainty)
Initial conditions uncertainty
Human actions (Human reflexive uncertainty)
Cox and Stephenson, Science, 2007
Accuracy versus Precision
High accuracyLow precision
Low accuracyHigh precision
‘Global mean temperature will increase between 1.4º and 5.8ºC by
the end of the century’
‘Maximum temperature in July will increase by 3.7ºC in Marseille in
2088...
Accuracy versus Precision
Climate variable
e.g. 20th percentil
e
Precise, but inaccurate
‘True’ valueProbability density
‘Accurate’, but imprecise
Not if we understand the wider contexts in which adaptation has to take place ...
... spatial planning, technical regulation, economic priorities,adaptive management, risk management, cultural preferences, risk psychology …..
So is climate adaptation in the water sector therefore limited?
Are there Alternatives to Predict-and-Adapt?
Predict-then-adapt approach Assess-risk-of-policy framework
Structure Problem
Characterise Climate Uncertainty
Design Adaptation
Evaluate Outcome
Outcome Optimised for Climate
Structure Problem
Propose Various Strategies
Assess Strategies Against a Wide Range
of Qt/Ql Futures
Summarise Trade-Offs Among
Promising Strategies
Outcome Optimised for Robustness
Adaptation (autonomous
)
Adaptation (with
investments)
x1
Climate parameter (e.g. rainfall)
Fre
qu
ency
Extremen Extremen
Drought risk
Flood risk
“Acceptable risk”
“Acceptable risk”
Adaptation (autonomous
)
Adapation (with
investments)
x1
Climate parameter (e.g.rainfall)
Fre
qu
ency
P1P2
x2
Climate Change
“Acceptable risk”
So What are the Implications for Water Management?
• Water managers expect decisions to be based on the ‘best
possible’ (read precise) scenarios
• But the science of climate modelling is unlikely to fulfil the
expectations of decision-makers and, through over-
precision, could potentially lead to mal-adaptation if
misinterpreted or used incorrectly
• Water sector will benefit much more from a greater
understanding of the vulnerability of climate-influenced
decisions to large irreducible uncertainties and in the
context of a broader set of socio-economic drivers...
Conclusions
We argue that the epistemological limits to climate model
predictions should not be interpreted as a limit to adaptation in
water sector, despite the widespread belief that it is ...
…there is no magic bullet precise climate scenario, there will always
be scenario ranges, probabilities/ensembles and plausible or
less plausible futures….
Conclusions
….climate scenario selection and must go hand in hand with the
target application, and it should be accompanied by broader
vulnerability, risk and cost-benefit analysis…
….selected adaptation measure should be robust and flexible
enough to reflect scenario and uncertainty ranges….
... climate adaptation strategies in the water sector can therefore be
developed in the face of these uncertainties…
Case1: Netherlands: Climate proofing in water….
“The climate is changing and we should make our country climate proof. The national government together with science, policy and other stakeholders”
Jan-Peter Balkenende - DutchPrime Minister, november 2005” Science - Policy
interaction
Map The Netherlands
Flooding area 1953
Netherlands: Are there technological limits to adapt?
Sea level rise: “plausible high end scenarios”
2100: + 0.55 - 1.20 m (0.65 – 1.35 incl. soil subs.)
Key importance of adaptive management: adapataion measures must be flexible, no-regret (robust) and hand in hand with monitoring & ability to incorporate new scientific insifghts
28
Sea level rise scenarios
Plausible high end scenarios ( = not to be excluded given the current state of the art science) are needed to test how robust the adaptation mesures are ( specific to flood protection and water safety applications)
Vlieland, 9 november 2007Breskens, 9 november 2007Katwijk, 9 november 2007
Noordwijk, 9 november 2007
“Building with Nature”
Flexible regarding changing conditions and societal values, and increased understanding
Cost-effective Opportunities for
integrated and multifunctional approach
Case2: Thames Gateway
Thames Gateway: properties at risk (floodplain)
2007: 29%
2016: 71%
1879 Flood Act >
Late C19 update to Flood Act >
1928 Flood & subsequent 1930 Flood Act >
Interim Defences during the construction of the Thames Barrier >
The traditional solutionProgressive defence raising along the Thames
The Thames Estuary 2100 project:
• planning for the 21st century
• addresses extreme (plausible high end) climate change
scenario
• considers demographic and social change
• stakeholder involvement
• examines range of options
1m0m 4m3m2m
Max water level rise:
Existing system
New barrier, retain Thames Barrier, raise defences
Raise Defences
Improve Thames Barrier and raise d/s defences
Note:
Each box represents one or more portfolios of responses
The arrows indicate paths for adapting options for different sea level ranges
Flood storage, over rotate Thames Barrier, raise d/s defences
New barrier, raise defences
Flood storage, raise d/s defences
New barrage
Over-rotate Thames Barrier and raise d/s
defences
Route 1
Route 3a
Route 3b
Route 4
Route 2
Flood storage, improve Thames Barrier, raise u/s & d/s defences
1m0m 4m3m2m
Max water level rise:
New barrier, retain Thames Barrier, raise defences
Raise Defences
New barrier, raise defences
New barrage
2050 2100
Medium High Climate Change Scenario
Route 1
Route 3a
Route 3b
Route 4
Route 2
All four Routes suitable in 2100
Alternative Routes for achieving the plan
Existing system
Improve Thames Barrier and raise d/s defences
Over-rotate Thames Barrier and raise d/s
defencesFlood storage, improve Thames Barrier, raise u/s & d/s defences
Flood storage, over rotate Thames Barrier, raise d/s defences
Flood storage, raise d/s defences
Note:
Each box represents one or more portfolios of responses
The arrows indicate paths for adapting options for different sea level ranges
1m0m 4m3m2m
Max water level rise:
New barrier, retain Thames Barrier, raise defences
Raise Defences
New barrier, raise defences
New barrage
Route 1
Route 3a
Route 3b
Route 4
Route 2
High++ Climate Change Scenario
Only route 4 suitable in 2100
(unless SoP reduced)
21002050
The final plan could be a combination of options
Existing system
Improve Thames Barrier and raise d/s defences
Over-rotate Thames Barrier and restore interim defences
Flood storage, improve Thames Barrier, raise u/s & d/s defences
Flood storage, over rotate Thames Barrier, raise u/s & d/s defences
Flood storage, restore interim defences
Note:
Each box represents one or more portfolios of responses
The arrows indicate paths for adapting options for different sea level ranges
Case 3: Melbourne Water Management
mJohn Thwaites, Minister for Water 2002 - 2007
Public anger as Water Supply Plummets
Climate Change and Melbourne’s Water Supplies
Preliminary Estimates for Melbourne
(no climate change) (low climate change) Yield (medium climate change)
(high climate change)
-
100,000
200,000
300,000
400,000
500,000
600,000
700,000
1994
/95
1999
/00
2004
/05
2009
/10
2014
/15
2019
/20
2024
/25
2029
/30
2034
/35
2039
/40
2044
/45
2049
/50
2054
/55
Date
Megalitr
es
Yield
Demand
2034202420192016
Shortfall by 2055 of 178 billion litres
Example: Preliminary estimates for Melbourne
Water Supply Plummets 2006
Water Crisis 2006
Conservation: Melburnians are the best water savers in the
nation
Recycling
Melbourne 1999: 4% recycling
Melbourne 2005/06: 14% recycling
Melbourne Target: 20% by 2010
Our Water Our Future
Four key principles:
1. Conservation
2. Increased recycling and stormwater use
3. Boosting supplies
4. Looking after rivers
Impact of Conservation on Storage Level
500 GL/Year Average
37
0 G
L
38
1 G
L
41
0 G
L
44
7 G
L
44
3 G
L
47
9 G
L
43
9 G
L
DEMAND:
Recorded storage levels Projected storage levels without conservation
0
10
20
30
40
50
60
70
80
90
100
July
/1996
July
/1997
July
/1998
July
/1999
July
/2000
July
/2001
July
/2002
July
/2003
July
/2004
July
/2005
July
/2006
July
/2007
July
/2008
July
/2009
July
/2010
Sto
rag
e v
olu
me
/ %
Lessons Learnt
With climate change it is difficult to predict water availability
Cannot rely on historic water data Climate Change impacts may be greater
than we thought
Positive Lessons Learnt: Conservation
2002 Strategy Target 12 % reduction per head by 2010
2006 Achieved 22 % reduction per head before strict
restrictions 2008
Achieved 36 % reduction per head more than the desalination plant supplies
Positive Lessons Learnt: Planning
A robust planning framework helped even if the predictions were wrong
Involved public early and changed attitude to water
Planning processes in place allowed adaptive management
Common alignment across water agencies and government
Thank you !