Prof. Dr. Pavel Kabat Wageningen University and Research Center, Netherlands

1. Climate and Water Can the water sector do anythingwiththe inherently uncertain climate change scenarios ? Prof. Dr. Pavel Kabat Wageningen University and Research Center, Netherlands Earth System Science & Climate Change Group www.ess.wur.nl Climate 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, UK Prof. Peter Cox, Exeter University & Hadley Centre, UK Prof. Joseph Alcamo, Kassel University & UNEP Prof. Kundzewich & IPCC 4AR colleagues

2. Worldwide Water Use by Region in km3 per year

3. Worldwide Water Use by Sector

4. The current situation 1.4 billion people in watersheds with < 1000m3/capita/year 2.4 billion people with poor sanitation 1 billion people without access to safe drinking water

5. IPCC 2007 ALL WATER RELATED (WATER DEPENDENT) SECTORS

7. Emissions Climate change Impacts Narratives Concentrations Climate scenarios chain………..

9. 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

10. Accuracy versus Precision ‘Global mean temperature will increase between 1.4º and 5.8ºC by the end of the century’ High accuracy Low precision ‘Maximum temperature in July will increase by 3.7ºC in Marseille in 2088... Low accuracy High precision

11. Accuracy versus Precision Probability density ‘True’ value Precise, but inaccurate ‘Accurate’, but imprecise Climate variable e.g. 20th percentile

15. So is climate adaptation in the water sector therefore limited? 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…..

17. Are there Alternatives to Predict-and-Adapt? Predict-then-adapt approach Assess-risk-of-policy framework Structure Problem Structure Problem Characterise Climate Uncertainty Propose Various Strategies Assess Strategies Against a Wide Range of Qt/Ql Futures Design Adaptation Evaluate Outcome Summarise Trade-Offs Among Promising Strategies Outcome Optimised for Climate Outcome Optimised for Robustness

18. Adaptation (with investments) “Acceptable risk” “Acceptable risk” Extremen Extremen Adaptation (autonomous) Drought risk Flood risk x1 Frequency Climate parameter (e.g. rainfall)

19. Climate Change “Acceptable risk” x2 x1 Adaptation (autonomous) P2 Adapation (with investments) Frequency P1 Climate parameter (e.g.rainfall)

20. 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...

21. 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….

22. 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…

23. 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 - Dutch Prime Minister, november 2005” Science - Policy interaction

24. Map The Netherlands Flooding area 1953

25. Netherlands: Are there technological limits to adapt?

27. 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) 28

30. Breskens, 9 november 2007 Noordwijk, 9 november 2007 Vlieland, 9 november 2007 Katwijk, 9 november 2007

31. “Building with Nature” • Flexible regarding changing conditions and societal values, and increased understanding • Cost-effective • Opportunities for integrated and multifunctional approach

37. Case2: Thames Gateway

38. Thames Gateway: properties at risk (floodplain) 2007: 29% 2016: 71%

39. Interim Defences during the construction of the Thames Barrier > 1928 Flood & subsequent 1930 Flood Act> Late C19 update to Flood Act > 1879 Flood Act> The traditional solution Progressive defence raising along the Thames

40. 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

41. Max water level rise: 0m 1m 2m 4m 3m Route 1 Improve Thames Barrier and raise d/s defences Route 2 Over-rotate Thames Barrier and raise d/s defences Flood storage, improve Thames Barrier, raise u/s & d/s defences Existing system Flood storage, over rotate Thames Barrier, raise d/s defences Raise Defences Flood storage, raise d/s defences Route 3a New barrier, retain Thames Barrier, raise defences Route 3b New barrier, raise defences Route 4 New barrage Note: Each box represents one or more portfolios of responses The arrows indicate paths for adapting options for different sea level ranges

42. Max water level rise: 2050 2100 0m 1m 2m 4m 3m All four Routes suitable in 2100 Route 1 Improve Thames Barrier and raise d/s defences Route 2 Over-rotate Thames Barrier and raise d/s defences Flood storage, improve Thames Barrier, raise u/s & d/s defences Existing system Flood storage, over rotate Thames Barrier, raise d/s defences Raise Defences Flood storage, raise d/s defences Route 3a New barrier, retain Thames Barrier, raise defences Route 3b New barrier, raise defences Route 4 New barrage Alternative Routes for achieving the plan Medium High Climate Change Scenario Note: Each box represents one or more portfolios of responses The arrows indicate paths for adapting options for different sea level ranges

43. Max water level rise: 2050 2100 0m 1m 2m 4m 3m Only route 4 suitable in 2100 (unless SoP reduced) Route 1 Improve Thames Barrier and raise d/s defences Route 2 Over-rotate Thames Barrier and restore interim defences Flood storage, improve Thames Barrier, raise u/s & d/s defences Existing system Flood storage, over rotate Thames Barrier, raise u/s & d/s defences Raise Defences Flood storage, restore interim defences Route 3a New barrier, retain Thames Barrier, raise defences Route 4 Route 3b New barrier, raise defences New barrage The final plan could be a combination of options High++ Climate Change Scenario Note: Each box represents one or more portfolios of responses The arrows indicate paths for adapting options for different sea level ranges

44. Case 3: Melbourne Water Management m John Thwaites, Minister for Water 2002 - 2007

45. Public anger as Water Supply Plummets

46. Climate Change and Melbourne’s Water Supplies Preliminary Estimates for Melbourne Example: Preliminary estimates for Melbourne Shortfall by 2055 of 178 billion litres

47. Water Supply Plummets 2006

48. Water Crisis 2006

49. Conservation: Melburnians are the best water savers in the nation

50. Recycling Melbourne 1999: 4% recycling Melbourne 2005/06: 14% recycling Melbourne Target: 20% by 2010