ClimateChange Assessment Guide.pdf - University of Waterloo

Climate Change Assessment6. Climate Change Assessment47This chapter is a step-by-step guide to conductingan assessment of the hydrological effects of climatechange in Ontario. Figure 6.1 shows the main steps toachieving a climate change impact assessment. Severalsteps are common to any hydrologic assessment andshould be completed prior to considering the impactsof climate change. That is, hydrologic models mustbe selected, setup, calibrated and verified as part ofan assessment of future land use and managementconditions, independent of climate change. For studieswith calibrated hydrologic models, the remainingcomponents of a climate change impact assessmentfocus on selecting the climate scenarios, developingfuture local climates (downscaling) and assessingthe impacts of the climate change scenarios throughmodelling applications.Guidance:All assessment steps outlined in this guidancedocument should be considered and addressedformally in a final report so that the study isthorough and contains all necessary components.6.1 Define Problem6.1.1 Goals and ObjectivesHydrologic and particularly climate change impactassessments are generally conducted for one or more ofthe following purposes:1. Determine how climate change will affect humanactivities and natural systems2. Evaluate risks, sensitivities, vulnerabilities andthresholds to change3. Screen and evaluate options for adaptation4. Determine costs of adapting or not adapting5. Determine potential effectiveness of adaptationoptions6. Identify information gaps7. Support public educationGuidance:Articulate the purpose of the study.In defining the purpose of the study, determine whetherthe stated purpose is a primary objective of the study orof secondary importance. Tier Three Water Budget andLocal Area Risk Assessments (Tier Three Assessments),for example, are conducted primarily to evaluate thereliability of municipal drinking water supplies, withspecial emphasis on the response and sensitivities ofthe natural system. It is possible, however, that the studymay be seen as an opportunity to examine and addresssome or all of the purposes listed above, although theseare not likely among the primary objectives.6.1.2 Issues and ConcernsGuidance:Specify issues/concerns for the hydrologic systemunder investigation.Figure 6.1 Climate change impact assessment stepsIn hydrologic systems, issues or concerns may bedefined as a potential water supply shortage or lowstreamflow under specific conditions, in specific areas or