Impacts of Climate Change onSettlements in the Western Port RegionPeople, Property and PlacesFinal Report: June 2008Printed on recycled stock.

AUTHORS:Peter Kinrade* and Benjamin Preston**With assistance from:Ian Macadam**, Tim Fisher*, Kym Whiteoak*, Nadja Wiedemann* andSarah Mirams* Marsden Jacob Associates ** CSIRO Climate Adaptation FlagshipAcknowledgementsProject funding provided by:Australian Government, Department of Climate ChangeDepartment of Sustainability and Environment, VictoriaThe authors wish to acknowledge valuable information and feedback provided by the followingproject steering committee and reference panel members:Western Port Greenhouse Alliance / Net Balance FoundationWestern Port Greenhouse AllianceAustralian Government, Department of Climate ChangeDepartment of Sustainability and EnvironmentBass Coast Shire CouncilCardinia Shire CouncilCity of CaseyFrankston City CouncilMornington Peninsula Shire CouncilBuilding CommissionCentral Coastal BoardDepartment of Justice, Office of the Emergency ServicesCommissionerDepartment of Human ServicesDepartment of InfrastructureDepartment of Planning and Community DevelopmentDLA Phillips FoxMelbourne WaterPort of Hastings CorporationSouth East WaterCONTACT:Michelle JustusGreg HuntTharman Saverimuttu, CrystalBakerJennifer Cane, Cathy Ronalds,Jack KrohnPaul Smith, Shaun YoungIan StevensonSonia Rappell, David Westlake,Michael JansenLibby Anthony, Sian Jones,Ossie MartinzRolf Freeman, Barry PankhurstDennis Hogan, Rob EnkerJacquie Mc LeodBrian Hine, Loriana BethuneBrian Kirkby, Noel CleavesMarianne RichardsFiona McKenzieKim PiskuricMark Warren, Gerard ThurbonRalph KenyonGordon LoganPeter Kinrade [email protected] Preston [email protected]


Impacts of Climate Change in the Western Port RegionEXECUTIVE SUMMARYIntroduction1.Since the mid-19th century, the average temperature at the Earth’s surface hasincreased by approximately 0.7 C (IPCC, 2007a). This warming is “verylikely due to the combined influences of greenhouse gas increases andstratospheric ozone depletion (IPCC, 2007a).”2.While much focus has traditionally been placed on building scientificunderstanding of such global changes in climate and their attribution,increasing attention is now focused on how communities, enterprises andgovernments should respond. This necessitates building understanding aboutthe local-scale implications of climate change that can be used to guideadaptive decision-making.3.This report examines the nature and extent of potential impacts of climatechange to the Western Port region of Victoria. The report’s focus is on theimpacts of climate change on the built environment, the social and economicimplications of the impacts and the vulnerability of different localities andgroups. It is one part of a wider ‘integrated assessment’ of climate change inthe region that covers: regional climate changes and biophysical impacts;socio-economic and infrastructure impacts (this report);risk assessment; andadaptation response.4.The Western Port region is well suited to a study of the impacts of climatechange on human settlements - it has a large, diverse and growing populationand a number of key implications of climate change are pertinent to the regionincluding coastal and inland flooding, wildfires and drought.5.In using this report it is important to be mindful of a range of uncertainties andlimitations associated with the various analyses of exposure and impacts.Profile of the Western Port region6.The Western Port region, which encompasses the local government areas ofBass Coast, Cardinia, Casey, Frankston and Mornington Peninsula Shire, hasa coastal climate with relatively mild temperatures and high rainfall comparedto other parts of Victoria.7.The region is comprised of a diverse economy and demography consisting ofkey residential hubs for metropolitan Melbourne, as well as thriving businessand industrial sectors. The region’s population is projected to grow byapproximately 45% by 2031, presenting many opportunities for economicexpansion and diversification, but also increasing the exposure of people,buildings and infrastructure to climate variability and change.8.Temperatures in the Western Port region have risen by approximately 0.05 Cto 0.15 C per decade since 1970, while annual rainfall has declined byapproximately 50 mm per decade.9.Climate models suggest temperatures in the region will increase by 0.5 to1.1 C by 2030 and 0.9 to 3.5 C by 2070, while average annual rainfall willFinal Reporti

Impacts of Climate Change in the Western Port Regionchange by -4 to 0% by 2030 and -23 to 0% by 2070. Meanwhile, sea-level riseprojections are uncertain, but the IPCC has estimated a range of 6 to 17 cm by2030 and 15 to 49 cm by 2070, with the potential for additional sea levelcontributions from acceleration of glacial ice melt.10.While these represent some of the projected changes in average climateconditions, climate extremes are projected to change as well, and it should berecognised that it is the changes in such extremes that are likely to pose themost significant threat to the region’s environments, infrastructure andcommunities in the years ahead.11.The Western Port region is significantly exposed to climate extremes andnatural hazards such as storm surge and coastal inundation, floods, bushfiresand extreme temperatures. These hazards are projected to increase infrequency and/or severity.12.Increased frequency or severity of climate hazards are projected to have abroad range of direct impacts on urban settlements (both market and nonmarket). These include impacts on land use and management, damages andmaintenance costs to public and private property and infrastructure, humanhealth and water availability. Increases in natural hazards will also haveindirect and intangible consequences including disruptions to economicactivity, the costs of emergency service provision, public amenity and qualityof life.13.Some of these impacts will be pervasive throughout the region; for others theextent of impact will be situation specific depending upon the spatialdistribution of hazards and human assets, populations and infrastructureacross the region and in local government areas.14.Specific climate consequences for the region’s settlements are outlined inTable A and discussed in more detail below.Impacts associated with coastal inundation15.Sea-level rise in future decades will undoubtedly affect the coastlines of theWestern Port region and drive progressive erosion in many locations. Theeffects of sea-level rise will however be most pronounced during stormevents. For example, storm surge inundation simulations for the region,undertaken by CSIRO for this assessment, suggest that a current 1 in 100 yearstorm surge could become a 1 in 1 to 1 in 4 year storm surge by 2070.16.Furthermore, the land area subject to inundation during a 1 in a 100 yearstorm surge event may increase by 4 to 15% by 2030 and 16 to 63% by 2070.17.The fact that only a narrow strip of land is exposed to coastal processes suchas storm surge means that the exposure of associated property, populationsand infrastructure is inherently constrained. Nevertheless, such inundationwould impinge upon over 2,000 individuals, over 1,000 dwellings, andapproximately 780 million in improved property value.18.Public infrastructure is also at risk, including major thoroughfares such as theNepean and South Gippsland Highways, and boating facilities. Beaches,foreshore reserves and coastal wetland areas throughout the region, as well asthe amenities they provide, are likely to be affected as well.Final Reportii

Impacts of Climate Change in the Western Port RegionTable A: Overview of Climate Change Impacts in the Western Port RegionClimate variableIndicative change*Sea level rise / storm surge(Chapter 3)20302070 up to up to0.17 m0.49 mStorm tide – max. height, 1:100year ARI (current 2.10 m, Cowes)2.29 m2.74 mStorm tide – max. height, 1:100year ARI (current 1.16 m,Frankston)1.37 mSea level rise to to1:40 - 1:61:20 - 1:1Inundation area Western Port Bay(1:100 year storm surge)up to12.6 sq kmup to17.7 sq kmInundation area Port Phillip Bay***(1:100 year storm surge)up to1.1 sq kmup to1.6 sq km2030 15-25 % 20-70 %12 hour 3-22 % 17-61 % 2 - 17 % up to 2,270 peopledirectly exposeddue to coarseresolution oftopographic data,people andproperties exposed toinundation may beunderstated,especially along PortPhillip Bay coastline20702 hour24 hour 1.80 mStorm surge – change to 1:100year ARIExtreme rainfall(Chapter 4)Exposed property andinfrastructure**Exposed people andland** 16-50 %72 hour 2-16 % 19-48 %Maximum flood heights flash riverine flash riverine up to 39,480 peopleup to 580 km2 of land Flood return intervals (ARI)Windiness and storms(Chapter 4, Box 3)2030 2070 Extreme winds 1 - 5 % 3 - 14 %entire population 1,030 residentialproperties 60 commercial and otherpropertiesmost beaches, coastalwetlands and foreshorereservesmost boating facilities 87km of roadssome drainageinfrastructurewater and sewer mains inBass Coast, Casey andMPSBass Coast: Cowes, Rhyll, Cape Woolamai Bass River Grantville, Coronet Bay possibly in vicinity of InverlochCardinia: no major settlementsCasey: Tooradin, WarneetFrankston City: most of central and northern foreshore Kananook Creek and surrounds, includingpossibly Frankston CAD and Seafordwetlands and surroundsMornington Peninsula Shire: Crib Point, Hastings, Shoreham and StonyPoint (Western Port Bay) possibly Balcombe Creek, Dromana Bay,Safety Beach, Dunns Creek, West Rosebud(Port Phillip Bay) 13,390 residentialproperties( incl. rural),( 3,200 dwellings) 2,050 commercial,industrial and otherpropertiespublic infrastructureincluding schools, healthcare facilities, hallsreserves and parks 1,412 km of roads, 26bridgesextensive drainageinfrastructurewater and sewer mainsand sewer pump stationsrailway linesBass Coast: Bass River flood plainCardinia: all of southern section of Shire / Koo WeeRup SwampCasey: much of eastern and southern sections of city significant pockets around Hallam, NarreWarren, Berwick (e.g. Hallam Main drain) andCranbourneFrankston: most of central and northern coastalhinterland Frankston CAD Seaford wetlands and surroundsMornington Peninsula Shire: Crib Point, Hastings, Shoreham and StonyPointolder buildingselectricity &telecommunicationsinfrastructureparks and gardensEconomicand social impactsMost sensitive locations exposed coastal and elevated areas tourismrecreation andboatinglocal governmentVulnerablegroups partial or (in worst case) completeloss of land values in affectedareasmajor amenity impacts associatedwith damage to beaches andforeshore reservesimpacts on businesses dependenton beach related tourismincreased insurance costs or lackof access to insurancecosts associated with beach andforeshore maintenance (e.g.beach renourishment)Vulnerablesectors increased flood damage to publicinfrastructure, especially roadsand bridgesincreased flood damage costs toresidential and commercialbuildings (minimal)disruption to transportincreased emergency servicesdemand and costslost agricultural productionhealth impacts related todisruption of water and sewerageservicesstress and social disruptionincreased damage costs toresidential, commercial and publicbuildingsincreased emergency servicecostsdisruptions to electricity supply local governmenttransportrural / agricultureresidential andcommercialutilities (drainage)emergencyservices emergencyserviceselectricity andtelecommunications low incomehouseholdselderlyhouseholdslow incomehouseholdsbusinessesand propertieswithoutadequateinsuranceresidenceswith limitedfreeboardabove 1:100year flood (e.g. 300 mmclearance)properties notadequatelyprepared ormaintainedresidents inlow qualityhousingproperties withlarge trees* Key to climate changes: increase; decrease; no significant change. Absence of number next to arrow indicates magnitude of change has not been quantified.** Based on current (2006) population and projected changes to 2070. *** Subject to considerable uncertainty.Final Reportiii

Impacts of Climate Change in the Western Port RegionClimate variableFire weather(Chapter 5)No. of very high and extremeforest fire risk days ( 9-12 dayscurrent)Indicative change*2030Exposed property andinfrastructure**Exposed people andland**2050 1-2 2-7 up to 73,620 people,mostly adjacent tobushlandup to 468 km2 of land No. of very high and extremegrass fire risk day