National Centre for Risk Analysis and Options Appraisal Climate Adaptation: Risk, Uncertainty and Decision-Making Dr. Robert Willows Environmental Forecasting Manager

National Centre for Risk Analysis and Options Appraisal Energy Demand Energy Supply Emissions Sequestration Climate Change Climate Variability Economic and Social Issues and Development Scenarios Policy Risk Analysis Forecast Models Options Appraisal Policy Analysis Uncertainty Analysis Sensitivity Analysis Tools Impacts Adaptation -ve Uncertainty

Help identify ‘climate-sensitive’ decisions Science Decision/ Policy makers Help achieve better decisions Provides guidance on the use of tools and techniques Should provide generic guidance on climate risks Consistent with DETR guidelines for Environmental Risk Assessment (‘Greenleaves 2’) Study objectives

National Centre for Risk Analysis and Options Appraisal UKCIP Technical Report Part 1 : A review of –Risk and uncertainty –Decision-making under uncertainty –Risk-based climate impact assessment Part 2 : Framework and Guidance –Stage by Stage guidance to support the process of undertaking risk-based appraisal of climate influenced decisions Climate Adaptation: Risk, Uncertainty and Decision Making

Decision Making Framework Climate change issue Climate change application Adaptation strategies Climate change research, monitoring Climate change policy Socio-economic scenarios Climate change scenarios Impact assessment Climate change policy Identify problem Implement decision Establish criteria for decision-making Monitor Risk assessment Options appraisal Identify options Vulnerability assessment Problem defined correctly ? Data information collection Yes No Make decision Objectives met ?

National Centre for Risk Analysis and Options Appraisal Risk = Hazard * Consequence Climate C 1.2 C 1.1 Decision Criteria C 1.3 C 3.1 C 2.1 C 3.2 Non-Climate C 4.1 Consequences HAZARD … PATHWAY … RECEPTOR

National Centre for Risk Analysis and Options Appraisal Hazard … Risk … and … Uncertainty Probability (cumulative) 1 0 Magnitude Large Small ?

National Centre for Risk Analysis and Options Appraisal Risk … and Uncertainty High Risk Low Risk Hazard High Low Consequence Large Small

National Centre for Risk Analysis and Options Appraisal Risk … and Uncertainty Knowledge of Hazard good poor Knowledge of Consequence goodpoor Quantitative Risk Uncertainty of likelihood Ambiguity Ignorance of risk

National Centre for Risk Analysis and Options Appraisal Risk Prioritisation – Temporally-dynamic risks Past or Present risk Rate of change of risk or future risk Higher priority Act sooner High Low High Low

National Centre for Risk Analysis and Options Appraisal Climate sensitive decisions Climate adaptation decisions Climate influenced decisions Climate independent decisions Large Moderate None Significance of climate change or climate variable(s) NoneModerateLarge Significance of non-climate factors or non-climate variable(s)

National Centre for Risk Analysis and Options Appraisal Decision errors? None ModerateLarge Perceived importance of factors Actual Importance of factors Over-adaptation Perceived importance of factors Actual Importance of factors Under-adaptation Perceived importance of factors Actual Importance of factors Mis-adaptation Climate factors Non-climate factors Actual importance of factors Perceived importance of factors Mal-adaptation

National Centre for Risk Analysis and Options Appraisal Adaptation strategies under Uncertainty Optimistic Precautionary ‘Risk Averse’ Least Regret No-regret – – The option the may produce the best adaptation outcome – – The option associated with the most favourable of the least favourable possible outcomes – – That option associated with the lowest lost opportunities or regret – – The best adaptation option under all possible outcomes MaxiMax MaxiMin MiniMax Regret

National Centre for Risk Analysis and Options Appraisal Generic options for climate risk management Wider use of risk assessment, forecasts and options appraisal – –preferably proactive technical response Delay and buy-time – – proactive technical response to reduce uncertainty Research  e.g. modelling, technology, ‘adaptive capacity’ Monitoring – – system performance monitoring - proactive technical response – – climate impact monitoring - reactive technical response Data and information supply, and education, awareness raising – – proactive and reactive Contingency planning – –low probability, high consequence events – –strategic planning response

National Centre for Risk Analysis and Options Appraisal Generic options for climate risk management Diversification or bet-hedging – –proactive technical or policy response Insurance  proactive, fiscal response Defend and Manage - reactive technical measures Change of use – –proactive or reactive, planning response +/- technical measures Retreat and Abandon – –strategic planning response Safety factors, climate headroom, buffering measures – –technical and regulatory response

National Centre for Risk Analysis and Options Appraisal Adaptation measures and options Adaptation not just “Defend, Managed Retreat, or Abandon” Informed by formal assessment of climate change risk, adaptation options may comprise a portfolio of different adaptation measure. These may include: Delay decisions, buy-time, data and information gathering, R&D, monitoring, contingency planning, bet-hedging, insurance/other risk spreading strategies, safety factors/headroom……….

Decision Making Framework Climate change issue Climate change application Adaptation strategies Climate change research, monitoring Climate change policy Socio-economic scenarios Climate change scenarios Impact assessment Climate change policy Identify problem Implement decision Establish criteria for decision-making Monitor Risk assessment Options appraisal Identify options Vulnerability assessment Problem defined correctly ? Data information collection Yes No Make decision Objectives met ?

National Centre for Risk Analysis and Options Appraisal See associated notes pages...

National Centre for Risk Analysis and Options Appraisal Risk screening - climate variable checklist Helps to both identify (Table 1) and define the different characteristics (Table 2) of potentially significant or relevant climate variablesHelps to both identify (Table 1) and define the different characteristics (Table 2) of potentially significant or relevant climate variables Includes preliminary assessment of sensitivity and confidenceIncludes preliminary assessment of sensitivity and confidence Useful for screening of variablesUseful for screening of variables Not constrained by availability of climate forecast variables (e.g. from GCM’s or RCM’s)Not constrained by availability of climate forecast variables (e.g. from GCM’s or RCM’s) Encourages rigorous analysis of climate influenceEncourages rigorous analysis of climate influence Table 1 is not complete - proxy and compound variables will depend on nature of particular assessmentTable 1 is not complete - proxy and compound variables will depend on nature of particular assessment

National Centre for Risk Analysis and Options Appraisal Climate variable checklist Examples Primary CO2, sea-level, temperature, precipitation, wind,cloud cover Primary CO2, sea-level, temperature, precipitation, wind,cloud cover Synoptic Weather types, pressure, storm track, lightning Synoptic Weather types, pressure, storm track, lightning Compound Humidity, evapotranspiration, mist, fog, growth season Compound Humidity, evapotranspiration, mist, fog, growth season Proxy Soil Moisture, river flow, wave climate Proxy Soil Moisture, river flow, wave climate Types of variables

National Centre for Risk Analysis and Options Appraisal Climate variable checklist Examples Magnitude and Direction Increase, decrease, rate of change Magnitude and Direction Increase, decrease, rate of change Statistic Average, time-integrated, variability and frequency Statistic Average, time-integrated, variability and frequency Averaging period Instantaneous... hourly …. Annual …..decadal Averaging period Instantaneous... hourly …. Annual …..decadal Joint probability events Consecutive, coincident or joint occurrence, Joint probability events Consecutive, coincident or joint occurrence, and variables correlation Characteristics of variables

National Centre for Risk Analysis and Options Appraisal (Climate) Influence diagrams Water level Structure Beach state Overtop Breach Flood Waves Flood event Extreme wave climate Beach morphology Extreme water level climate Changes to structure Mean water level Surges Land level Tides Rainfall, freeze/thaw, wave damage, animal activity, vegetation ‘Everyday’ wave climate Wind speed direction Global temperature Atmospheric pressure Climate

National Centre for Risk Analysis and Options Appraisal Describing confidence ….. Subjective descriptorQuantitative probabilistic descriptor HazardCertainty Theoretical basis or model Information or data Peer acceptance Colleague acceptance Pedigree rank score P > 95%‘Highly probable’ ‘Very likely’ ‘Certain’, ‘Known’ ‘Reliable’ Established, Validated model Experiment- al Absolute‘All but cranks’ 4 75% < P < 95%‘Likely’ to ‘Probable’ ‘Confident’Process- based model, underpinned by some theory Historical or Observation High‘All but rebels’ 3 25% < P < 75%‘Possible’‘Plausible’ ‘Debatable’ Black box and Simulation models CalculatedMedium‘Different schools’ 2 5% < P < 25%‘Unlikely’ to ‘Improbable’ ‘Not confident’ ‘Uncertain’ ‘Doubtful’ Statistical models Fuzzy models Educated or expert guess Low‘New field’1 P < 5%‘Impossible’Concepts and definitions Uneducated or non- expert guess None‘No opinion’ 0

National Centre for Risk Analysis and Options Appraisal Downscaling 1 Space: GCM  site Time: Monthly  daily

National Centre for Risk Analysis and Options Appraisal SDSM - Statistical Down-Scaling Model (Rob Wilby, Kings College London) – –Daily data - observed data at site – –Model - site data and large-scale data from GCM – –Scenario - generate ensembles of daily time series

National Centre for Risk Analysis and Options Appraisal Downscaling - Flood return period prediction 1860 climate 2000 climate 2090 climate

National Centre for Risk Analysis and Options Appraisal Scenario analysis and risk assessment Q.Can we create scenarios which reflect changes in variability as well as the mean? A. Probably. Expert judgement can be used to assign probability to the range encompassed by any two scenarios … but uncertainty components within suite of scenarios have to be well-posed YES - but it is difficult… and scenarios remain contingent on assumptions and non-quantified uncertainties A. YES - but it is difficult… and scenarios remain contingent on assumptions and non-quantified uncertainties Q. Can we assign probabilities to different scenarios?

National Centre for Risk Analysis and Options Appraisal Estimating “probabilities” of different futures We typically use a small number of scenarios If we make assumptions about the likelihood of different emissions futures, use many more climate models, and incorporate the effects of natural climatic variability, we can generate many more scenarios

National Centre for Risk Analysis and Options Appraisal Probabilistic scenarios Scenario (Subjective) Probability 0 1 L->M L->MH L->H Scenario (Subjective) Probability 0 1 L M MH H

National Centre for Risk Analysis and Options Appraisal Incorporating climate change into water resources management The future hydrological resource base will not be the same as the present resource base Mean climate will be different, due to climate change and natural climatic variability Variability in climate will be different. Altered frequency of successive dry years? ….but we don’t know how different….

National Centre for Risk Analysis and Options Appraisal hydrological model water resources model reliability Demand-side Supply-side demand land use change Climate change baseline data management objectives adaptive response Influence diagrams - water resource management

National Centre for Risk Analysis and Options Appraisal Use of socio-economic scenarios Forecast demand in s of Ml/d Water resources for the future A STRATEGY FOR ENGLAND AND WALES March 2001

National Centre for Risk Analysis and Options Appraisal Coping with uncertainty 1.Flexible management approaches - review situation and adjust plans if appropriate - continued monitoring 2.Improved seasonal forecasts - based on understanding of causes of seasonal climatic variability 3.Scenario analysis and risk assessment

National Centre for Risk Analysis and Options Appraisal Conclusions and recommendations (for decision-makers) Emphasis on understanding impact of present-day observed climate variability Future climate change is only one source of decision uncertainty Assessment of climate risk should be hierarchical /tiered Climate adaptation should be iterative Assumptions and sources of uncertainty should be treated explicitly in risk and impact assessments in order to reach robust decisions