How climate proof is the Dutch water management? Survey for ‘adaptation tipping’ points in water management and policy Jaap Kwadijk, Deltares Ad Jeuken, Deltares Harold van Waveren, RWS-Waterdienst

Climate is not the only thing that changes in 100 years 1900->2000 ~ 2000->2100

Content Approaches to deal with scenarios, top-down and bottom-up Quality and value of scenarios Express uncertainty in terms of time to react More and less urgent issues to prepare for What river discharges can we expect When will the current protection along the rivers fail

Population and economical growth energy demand land use Greenhouse gas emissions Greenhouse gas concentration in the atmosphere Hydrologic effects Energy-economy models carbon cycle models Global + regional climate models Global/regional climate projections Hydrologic + hydraulic modellen Water management Measures Classical approach to arrive at water management scenarios

Status of the climate projections  Reasonable agreement on the trends  Much less agreement on the speed and magnitude.  Certainly too little agreement to design water management systems according to classical approaches (WMO, 1987) Continuous effort to improve the projections is needed for the sake of science. HOWEVER the potential that point 3 will be solved in the next 5-10 years is VERY LOW

So the difficulty in communication between hydrologists and decision makers (part I) “ You have a problem, the climate is changing ! “ Hydrologist Decision maker

“ How much….? “ So the difficulty in communication between hydrologists and decision makers (part I) Hydrologist Decision maker

The difficulties of adaptation to climate change Time horizon is very long, => no urgency in comparison with the daily trouble Adaptation plays at different institutional/ policy levels, no clear owner Impact might be beyond what we can imagine “Tragedy of the commons” : CC is important, however others should solve it (after Geert Teisman, Routeplanner, 2007)

Approach for climate adaptation Hulme and Dessai, 2004, (uit vd Dessai en vd Sluis, 2008

Key elements Adaptation to climate change in the Netherlands has no value in itself. We do this because we want to live, work etc. in the Rhine-Meuse delta. => We ask the question, how much should the climate change before we are in trouble (climate change = change in natural boundary conditions) This is what we call an “adaptation tipping point”

Vulnerability of the water management system An approach to explore the limits of the current strategies in view of the different and changing climate scenario’s. The quality of the climate prediction is not the most interesting but the value

The Quality of the scenario is the scenario based on sound scientific theory, are the assumptions consistent, has the correct statistical analysis been used, are the models used physically sound etc. etc.

The value of the scenario Would I take another decision if the climate changes (=>) So only those scenario’s are interesting that provide the stakeholder a perspective to do something

Quality and Value of a climate change projection (free after Micha Werner) Climate change scientist Get data Provide climate projections Change my strategy? Risk of too few / too much measures Water manager Inform people Projection Quality Can I provide a more accurate projection Hydrologist Projection Value Should I make another decision Improve models Improve downscaling Understand natural processess Run models

The Quality Is the scenario based on sound scientific theory, are the assumptions consistent, has the correct statistical analysis been used, are the models used physically sound etc. etc. The Value Would I take another decision if the climate changes (=>) So only those scenario’s are interesting that provide the stakeholder a perspective to do something The Quality of the scenario Scientists Decision makers

Short term (Policy maker) perspective Question for a policymakers time frame Is there a risk that policy targets will not be achieved Is there a risk that additional measures will be needed soon (extra money needed) Is there a risk that too much measures are taken (too much money is spend) Strategic questions How long will the strategy be efficient after the time horizion (robustness). How easy is it to change in time to an alternative strategy (flexibility/no regret).

Try to support the decision maker on identifying : What are the most important issues When will the current strategy fail What are possible strategies Between which boundary conditions (e.g. water levels, salt concentration, temperature range a strategy is efficient When should be started to prepare for alternative strategies => carry out a sensitivity analysis for the water management system: try to answer, how much change can I handle before I run into trouble (= adaptation tipping point). => once determined, use different scenario’s to assess the min/max available time to react (start alternative strategies/ initiate measures etc) For decisions time is important: try to express the uncertainty in terms of time instead of magnitude of change

Strategic questions How long will the strategy be efficient after the time horizion (robustness). How easy is it to change in time to an alternative strategy (flexibility/no regret).

Approach 1.Define a long list of possible (effects of) climate changes and impacts 2.From long list to short list : urgency matrix (use trends+extreme scenarios) 3.Determine how much change sectors can handle (without too much trouble => adaptation tipping points, independent from time) 4.Use existing scenario (eg IPCC, or from national agencies) to assess when the change will be probably too much (=> at that time alternatives should be ready) 5.Determine alternative strategies (methods depend on scale, score these alternatives to policy targets) 6.Carry out for these alternatives + assess how easy it is to switch in time (flexibility) => decision tree

Step 1: Long list of possible (effects of) climate changes and impacts Rows. Effects of climate change + scores of likelyhood Cols: Impacts (on flood safety, fresh water supply, economic activities (navigation, drinking water, power production + scores of level of importance.

Step 2: From long list to short list : urgency matrix When carried out with stakeholders provides commitment to those issues that need to be addressed

Step 3 Finding tipping points Determine under what changes of boundary conditions the strategy it is no longer effective methods: compare with design criteria; consult epxerts/ representatives from different sectors; assess historical variation of boundary condidtions When (at the earliest latest) do we expect that this will be the issue methods: use climate scenario’s, extreme/moderate (depends on sector); interpolate beteen projection year and now; express uncertainty earliest date/ latest date that a CC will have reached a certain change will

Step 5+6 : Tipping points and Decision trees J. Kwadijk, M. Haasnoot, M. Hoogvliet, A. Jeuken, R. van de Krogt, N. van Oostrom, H. Schelfhout, E. van Velzen, M. de Wit, H. van Waveren Klimaatbestendigheid van Nederland als waterland. H2O 23/2008 (in Dutch). The Netherlands Climate proof.

Some impacts in coastal areas (years based on most extreme scenario’s) Fresh water supply will be severely hindered through salt water intrusion through the rivers (becomes an issue not before 2040) Spatial planning in urban areas along tidal rivers (becomes an issue not before 2050) Estimated speed of sea level rise according to higher SLR-scenario’s is very close or exceeds natural adaptive capacity of the Wadden sea and SW-Delta (sedimentation rates / erosion) Drowning of plates (with rise > 3 mm/year) (issue not before 2050). Storm surge barrier (Maeslantkering) designed for SLR up to 50cm (becomes an issue not before 2060) Accessibility Rotterdam Harbour hindered (Storm surge barrier needs to close more than once a year at SLR 75cm (becomes an issue not before 2080)) Coastal flood defence through sand supply (becomes an issue not before 2100 / or if sand cannot anymore be collected from the North Sea)

Findings (short) Experience:  Enables more to balance the risk of CC with other risks  Closer to the experience of the policymaker/ watermanager/ stakeholder  Allows for a dialogue between scientific world and water management world.  expressing uncertainty in time (when will a critical point be reached) is easier to understand than % change in a certain projection year.  Some times far from trivial (not the silver bullet) because……

“ Our water system is very robust ! “ So the difficulty in communication between hydrologists and decision makers (part II) Hydrologist Decision maker

“ How much change can it handle..?? “ So the difficulty in communication between hydrologists and decision makers (part II) Hydrologist Decision maker