Coping with Climate Risk climate sensitivity, coping ranges and risk

1. Coping with Climate Riskclimate sensitivity, coping ranges and risk AIACC Training Workshop on Adaptation and Vulnerability TWAS, Trieste June 3-14 2002 Roger N. Jones

2. Coverage • Impacts are sensitive to climate variability and extremes • Coping ranges as a tool to understand the relationship between V, I and A. • Operationalising coping ranges for risk assessment

3. Impacts are sensitive to climate variability and extremes Sensitivity to climate is: how much a system or activity is affected by climate-related stimuli

4. InsensitiveUnaffected by rain, hail, sun, wind or snow

5. SensitiveEasily affected by rain, hail, sun, wind and snow

6. Sensitivity to what?

7. Extreme temperature

8. Extreme temperature Increasing stress

9. How do we assess extremes? In two ways, rarity and impact: 1. As a rare event 2. As an event with extreme outcomes Extreme events are rare events with significant impacts, but under climate change may become more common

10. Types of extreme climate events

11. Confidence levels Climate Variable Atmospheric CO2 concentration Global-mean sea-level Global-mean temperature Regional seasonal temperature Regional temperature extremes Regional seasonal precipitation/cloud cover Changes in climatic variability (e.g. El Niño, daily precipitation regimes) Rapid or non-linear change (e.g. disintegration of the West Antarctic Ice Sheet) High confidence Low confidence Very low or unknown

12. Modelling climate variability Most impacts are sensitive to climate variability rather than the mean (atmospheric CO2 is a notable exception) Climate models represent climate variability relatively poorly Realistic and plausible scenarios of climate variability are needed

13. Socio-economic system Climate system Impacted activity Current climate Current adaptations Future climate Future adaptations Linking climate to impacts

14. IPCC 1994

15. Two approaches to V&A V = I – A V =  I – A, t t = 0, current climate, reference or baseline Time t relates to the planning horizon

16. Coping with climate (variability and extremes) A system can cope with some combinations of climate but other combinations will cause damage The ability to cope is a function of the sensitivity of a system to climate and its response to that sensitivity This response is the interaction of socio-economic and biophysical factors

17. Coping range under current climate

18. Coping range under current climate - limited ability to cope

19. Coping range structure (1) A coping range exists where climate – socioeconomic interactions are beneficial or suffer only tolerable damage. The width of the coping range is in part due to historical adaptation It is separated from an area of vulnerability by a threshold. The threshold can be critical, marking a level of harm that is intolerable, or mark a given level of hazard Beyond the coping range and threshold is a zone of vulnerability

20. Coping range structure (2) Simple Expressed in terms of one or two climate variables (e.g. rainfall, temperature) Complex Expressed in terms of secondary or tertiary variables with a known relationship with climate(e.g. stream flow, crop yield, rates of infectious disease)

21. Coping range dynamics Two aspects of the coping range can change: 1. Climate 2. Socioeconomic (affecting the width of the coping range) a. autonomous socioeconomic change may increase or decrease the width b. climatic events may trigger a contraction (through damage) or an expansion (adaptation to similar future events) We would like to add c. expansion to reduce anticipated future vulnerability

22. Changing coping range - socioeconomic change

23. Changing coping range - response to climate stress

24. Future climate - no adaptation

25. Policy Horizon Future climate with adaptation

26. Thresholds A non-linear change in a measure or system, signalling a physical or behavioural change Climate-related thresholds are used to mark a level of hazard

27. Thresholds as climate hazards There are two ways to construct climate hazards to use as thresholds 1.Natural hazards approach – a fixed threshold such as 1 in 100-year flood, storm surge or given storm strength applied over time and space. Especially good for locating most vulnerable areas. 2. Vulnerability-based approach – the climatic conditions resulting in a degree of harm that exceed the limits of tolerance. Usually specific to a given activity and location (e.g. drought, water supply, crop yields). Useful when constructed with stakeholder participation.

28. Biophysical (simple to complex) Tropical cyclone Coral bleaching ENSO event Island formation Island removal Socioeconomic (usually complex) Legal/regulatory Profit/loss Cultural Agricultural Critical Thresholds

29. A level considered to represent an unacceptable degree of harm This is a value judgement and may be decided by stakeholders, be a legal requirement, a safety requirement, a management threshold etc Critical thresholds

30. Planning horizons

31. Using coping ranges to assess risk– current risk • Choose a reference or baseline period pertinent to both climate and the socioeconomic background • Calculate threshold exceedance based on climate exposure during the reference period • Existing adaptations and those needed to reduce risk under present climate provide the short-term options for a ‘win-win’ adaptation strategy (helping cost-benefit and efficiency criteria)

32. Using coping ranges to assess risk– future risk • Each scenario will give a different probability of threshold exceedance • If using single, or several scenarios, these should be related to the full range of uncertainty for climate change, when communicating results • The effect of climate and socioeconomic scenarios can be assessed separately or together • Methods can range from semi-quantitative (simple) through to the application of advanced probabilistic techniques (difficult but interesting)

33. What is a risk? Two uses 1. In general language 2. A specific operational meaning

34. Characterising risk Risk is a combination of hazard, likelihood and vulnerability, i.e. stress, how likely that stress is, and how much damage that stress will cause.

35. Natural hazards approach to risk Fixed climate hazard - e.g. 1/100 flood, hurricane. Likelihood - frequency of occurrence; likelihood that it will occur Vulnerability - damage incurred Risk = f(hazard*likelihood, vulnerability)

36. Natural hazards approach to risk Examples Heat stress - hastened mortality per 103 or 105 population Flood damage mapping (e.g. $$ damage or dwellings inundated per 100 year flood) Storm damage mapping (structural damage for a given windspeed in $$ or no. of buildings damaged) Disease mapping (vector density aligned with infection rates) ENSO frequency and intensity aligned with known hazards

37. Vulnerability-based approach to risk Level of climate associated with given level of harm, e.g. critical threshold Likelihood - frequency of occurrence; likelihood that it will occur Risk = f(hazard*vulnerability, likelihood)

38. Example - water supply for irrigation and wetland management Macquarie catchment - Australia Climate baseline: Daily P and Ep data 1890-1996 infilled across the catchment Management reference: 1996 infrastructure and catchment management rules Irrigation water allocation is capped and supply is shared between irrigation and environmental flows through the Macquarie Marshes Thresholds Supply of 350 GL into the Macquarie Marshes for waterbird breeding Irrigation water allocation of 0%, 50% or 100%

39. Simulated flow into the Macquarie Marshes - baseline case

40. Simulated flow into the Macquarie Marshes -10% flow (IS92c HCM3)

41. Simulated flow into the Macquarie Marshes -10% flow (IS92c HCM3)

42. Simulated irrigation allocations baseline and -10% flow (IS92c HCM3)

43. Simulated irrigation allocations baseline and -10% flow (IS92c HCM3)

44. 15 -40 -30 -10 -20 Exceeding critical threshold 0 10 Potential evaporation change (%) 5 10 IS92c HCM3 0 20 -5 0 -10 -5 5 10 Rainfall change (%) Sensitivity analysis for Burrendong Dam storage

45. 15 -40 -30 -10 -20 0 10 Potential evaporation change (%) 5 10 0 20 -5 0 -10 -5 5 10 Rainfall change (%) Sensitivity analysis for Burrendong Dam storage Driest (SRES) Exceeding critical threshold Wettest (SRES)

46. Changes to MAF for 9 models in 2030 (%)Based on IPCC 2001 A1T at 4.2°C 1.27°C B1 at 1.7°C 0.55°C A1 at 2.5°C 0.91°C

47. Cumulative Probability (%) <100 <95 <90 <80 <70 <60 <50 Changes to Burrendong Dam storage 2030

48. Probabilities of flow changes - impacts view Range of possible outcomes

49. Basic principles • Pay greater attention to recent climate experience. Link climate, impacts and outcomes to describe the coping range. • Address adaptation to climate variability and extremes as part of reducing vulnerability to longer-term climate change. • Assess risk according to how far climate change, in conjunction with other drivers of change, may drive activities beyond their coping range. • Focus on present and future vulnerability to ground future adaptation policy development in present-day experience. • Consider current development policies and proposed future activities and investments, especially those that may increase vulnerability.