Climate Change in the Sydney Metropolitan Catchments Prepared for the New South Wales Government by the CSIRO

NEW SOUTH WALES GOVERNMENT | CSIRO

Border Rivers-Gwydir Murrumbidgee Central West Namoi Hawkesbury-Nepean Northern Rivers Hunter-Central Rivers Southern Rivers Lachlan Sydney Metro Lower Murray-Darling Western Sydney Metro Murray www.greenhouse.nsw.gov.au | www.csiro.com.au NEW SOUTH WALES GOVERNMENT | CSIRO

Austroads. 2004. Impact of Climate Change on Road Infrastructure. Howden, M., Hughes, L., Dunlop, M., Zethoven, I., Hilbert, D., Austroads Incorporated, Sydney, Australia, 124 pp. Chilcott, C., and Crutch, G. 2003. Report on BDAC workshop Want to on Climate Change Impacts on Biodiversity in Australia, CSIRO Bates, B.C. Charles, S.P. Chiew, F., Harle, K., Howden, M., Kirby, M., Sustainable Ecosystems and Environment Australia, Canberra. Peel, M., Suppiah, R., Siriwardena, L., Viney, N.R. and Whetton, P.H. 2003. Climate Change Projections and the Effects on Water Yield Howden, M., and Jones, R. 2001. Costs and Benefi ts of CO2 Increase know and Water Demand for the Australian Capital Territory. Consultancy and Climate Change on the Australian Wheat Industry. Australian report for ACT Electricity and Water. Greenhouse Offi ce, Canberra. more Beare, S., and A. Heaney 2002. Climate Change and Water Howden, S.M., McKeon, G.M., and Reyenga, P.J. 1999a. Climate Resources in the Murray Darling Basin, Australia: Impacts and change impacts on heat stress and water requirements of cattle Adaptation. ABARE Conference Paper 02.11, 33 pp. in Australia. In Global Change Impacts on Australian Rangelands. CSIRO Wildlife and Ecology,Working Paper Series 99/09, Canberra, about Burke, E.J., Brown, S.J., and Christidis, N. 2006. Modelling the ACT, Australia, pp. 38-51. recent evolution of global drought and projections for the twenty- fi rst century with the Hadley Centre climate model. Journal of Howden, S.M., Reyenga, P.J., and Meinke, H. 1999b. Global Change Climate Hydrometeorology 7, 1113-1125. Impacts on Australian Wheat Cropping. Working Paper Series 99/04, CSIRO Wildlife and Ecology, Canberra, Australia, 121 pp. Charles, S.P., B.C. Bates, and N.R. Viney 2002. Linking atmospheric circulation to daily rainfall patterns across the Murrumbidgee River Howden, S.M., Reyenga, P.J., and Gorman, J.T. 1999c. Current Change? Basin. Proc. 5th International River Symposium, 3-6 September 2002, Evidence of Global Change and its Impacts: Australian Forests and Brisbane, Qld, Australia. Other Ecosystems. CSIRO Wildlife and Ecology Working Paper 99/01, 23 pp. Cowell, P.J. Thom, B.G., Jones, R.A., Everts, C.H., and Simanovic, A number of D. 2006. Management of uncertainty in predicting climate-change IDRO (International Disasters Response Organisation) 2006. Major impacts on beaches. Journal of Coastal Research 22, 232-245. Disasters Since June 1967 - Revised to March 2006. Accessed 14 April climate change 2006 [Australia and New Zealand; Disaster]. DEC (Department of Environment and Conservation) 2006. studies relevant Threatened Species: Species, Populations, and Ecological Jones, R.N., and Hennessy, K.J. 2000. Climate Change Impacts Communities of NSW. Accessed October, 2006. in the Hunter Valley – A Risk Assessment of Heat Stress Affecting Dairy Cattle. CSIRO Atmospheric Research report for the NSW to the Sydney Hassall and Associates. 1998. Climatic Change Scenarios and government, 26 pp. Managing the Scarce Water Resources of the Macquarie River. Metropolitan Australian Greenhouse Offi ce. Hassall and Associates, New South Jones, R.N., and Page, C.M. 2001. Assessing the risk of climate Wales Department of Land and Water Conservation, New South change on the water resources of the Macquarie River catchment. Catchments are Wales National Parks and Wildlife Service, and CSIRO Atmospheric In: Integrating Models for Natural Resources Management across listed here: Research, Canberra, Australia, 113 pp. Disciplines, issues and scales (Part 2), MODSIM 2001 International Congress on Modelling and Simulation, [Ghassemi, P., Whetton, P., Hennecke, W.G. 2004. GIS modelling of sea-level rise induced Little, R., and Littleboy, M. (eds.)], Modelling and Simulation Society shoreline changes inside coastal re-entrants - Two examples from of Australia and New Zealand, Canberra, pp. 673-678. southeastern Australia. Natural Hazards 31, 253-276. McDonald, W. 2006. CSIRO Submission: A sustainable water supply Hennessy, K.J., and Clayton-Greene, K. 1995. Greenhouse warming for Sydney. NSW Legislative Council General Purpose Committee and vernalisation of high-chill fruit in southern Australia, Climatic No. 5, Sydney, NSW, Australia. Change 30, 327-348. McMichael, A.J., Woodruff, R.E., Whetton, P., Hennessy, K., Nicholls, Hennessy, K., Page, C., McInnes, K., Jones, R., Bathols, J., Collins, N., Hales, S., et al. 2003. Human Health and Climate Change in D., and Jones, D. 2004. Climate Change in New South Wales. Part 1. Oceania: A Risk Assessment. Commonwealth Department of Health Past Climate Variability and Projected Changes in Average Climate. and Ageing, Canberra, Australia. Consultancy report for the New South Wales Greenhouse Offi ce by CSIRO and the Australian Bureau of Meteorology. Minnery, J.R., and Smith, D.I. 1996. Climate change, fl ooding and urban infrastructure. In: Greenhouse: Coping with Climate Change Hennessy, K., Page, C., McInnes, K., Jones, R., Bathols, J., Collins, [Bouma, W.J., G.I. Pearman, and M.R. Manning (eds.)]. CSIRO D., and Jones, D. 2004. Climate Change in New South Wales. Part 2. Publishing, Collingwood, Victoria, Australia, pp. 235-247. Projected Changes in Climate Extremes. Consultancy report for the New South Wales Greenhouse Offi ce by CSIRO and the Australian PIA. 2004. Sustainable Regional and Urban Communities Adapting Bureau of Meteorology. to Climate Change: Issues Paper. Planning Institute of Australia, Queensland Division, Brisbane, 88 pp. Hennessy, K.J. Lucas, C., Nicholls, N., Bathols, J., Suppiah, R., and Ricketts, J. 2005. Climate Change Impacts on Fire-Weather in Pickering, C.M., Good, R., and Green, K. 2004. Potential Effects of Southeast Australia. CSIRO Atmospheric Research. Consultancy Global Warming on the Biota of the Australian Alps. A report for the report jointly funded by the Commonwealth of Australia and the Australia Greenhouse Offi ce. governments of New South Wales, Victoria, Tasmania, and the Reyenga, P.J., Howden, S.M., Meinke, H., and Hall, W.B. 1999. Global Australian Capital Territory, 91 pp. Change Impacts on Wheat Production along Two Environmental Howden, S.M., Ash, A., Barlow, S., Booth, T., Charles, S., Cechet, Gradients in Australia. Working Paper Series 99/12, Report to the R., Crimp, S., Gifford, R., Hennessy, K., Jones, R., Kirschbaum, M., Australia Greenhouse Offi ce, CSIRO Wildlife and Ecology, Canberra, McKeon, G., Meinke, H., Park, S., Sutherst, R., Webb, L. and Whetton, Australia. P. 2003. An Overview of the Adaptive Capacity of the Australian Schreider, S.Y, Smith, D.I., and Jakeman, A.J. 2000. Climate change Agricultural Sector to Climate Change – Options, Costs and Benefi ts. impacts on urban fl ooding. Climatic Change 47, 91-115. CSIRO Sustainable Ecosystems, Canberra. Smith, D.I. 1998. Urban fl ood damage under greenhouse conditions: Howden, S.M., and Crimp, S. 2001. Effect of climate change on What does it mean for policy? Australian Journal of Emergency electricity demand in Australia. In: Proceedings of Integrating Management, 13(2), 56-61. Models for natural resource management across Disciplines, Issues and Scales. Modsim 2001 International Congress on Modelling and Webb, L.B. 2006. The Impact of Projected Greenhouse Gas-Induced simulation. Ghassemi, F., P. Whetton, R. Little, and M. Littleboy (eds.). Climate Change on the Australian Wine Industry. PhD Thesis. Modelling and Simulation Society of Australia and New Zealand, University of Melbourne, Melbourne, Australia. Canberra, pp. 655-660.

For the latest The NSW Greenhouse Ofﬁ ce website: This site provides the latest news on catchment information on www.greenhouse.nsw.gov.au management projects and programs, relevant climate change, This site contains more information on what the policies, and access to brochures and publications its consequences NSW Government is doing to combat climate related to management of the catchment. change, including downloadable copies of the and tools for The Australian Greenhouse Ofﬁ ce’s National Climate NSW Greenhouse Plan. managing risk, Change Adaptation Program: www.greenhouse. visit the following The Sydney Metropolitan Catchment gov.au/impacts/index.html#programme web pages: Management Authority: http://www.sydney.cma.nsw.gov.au/index.html www.greenhouse.nsw.gov.au | www.csiro.com.au NGH0002.SYDNEY www.pirocreative.com.au SydneySydney

The Earth’s plants and animals depend on Evidence of Australian 1.0 the climate to which they are exposed – they Climate Change benefi t when conditions are favourable, and The they suffer when conditions become extreme. • Average temperatures in Australia rose Humans are no exception. 0.9°C from 1910 to 2004. There have been Problem more heatwaves and fewer frosts. The crops and water resources that we • Since 1950, annual rainfall has declined use to sustain our communities are linked of on the eastern seaboard and in the south to the climate, and the economic as well of the continent, but increased in the as human losses that we experience Climate northwest. from hail, cyclones, fl oods, droughts and Change bushfi res are a reminder of our ever-present • Since 1973, droughts have become more vulnerability to the climate system. intense, and extreme rainfall events have increased in the northeast and southwest. It is increasingly clear that our climate is changing. Whereas in the past humans According to the United Nations’ have learned to cope with climatic variability Intergovernmental Panel on Climate Change and change that was natural in origin, “most of the warming observed over the last we are now living in a climate of our own 50 years is attributable to human activities.” making. The rate at which our climate These activities – mainly the burning of fossil is being transformed is unprecedented fuels such as coal, oil, and natural gas – have throughout much of human history. released vast quantities of greenhouse gases into the atmosphere. Evidence of a Changing Global Climate

• Temperatures in the northern hemisphere at the end of the 20th century are believed to have been warmer than they have been at any time in the previous 1,000 to 2,000 years. • The average global temperature in 2005 was the warmest on record, and eight of the ten warmest years have occurred since 1997. • The Earth’s average surface temperature has risen 0.7°C since 1900. • Heatwaves and extreme rainfall have become more common in many regions. • The sea level has risen 1.8 mm per year since 1950 and that rate is accelerating. • There have been fewer frosts and the ice sheets of Antarctica and Greenland are shrinking. • The timing of physiological processes in plants and animals is changing throughout the world, and populations are shifting their distributions.

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Much of the energy that drives the Earth’s This trapping of heat energy is known as the 1.1 natural processes comes directly from the Sun. ‘greenhouse effect’ – keeping temperatures Around half of the Sun’s energy that reaches higher than they otherwise would be, just like What is the Earth breaks through the atmosphere, a glass greenhouse keeps plants warm (Figure warming the surface of the planet. The land 1). Without this process, the global average and oceans then radiate that heat, some of surface temperature would be closer to minus Causing which is trapped by greenhouse gases in the 18°C, instead of the current 15°C. atmosphere. The principal greenhouse gases Climate are water vapour, carbon dioxide, methane and The problem we now face is that human Change? nitrous oxide. actions - particularly burning of fossil fuels, Figure 1. The Greenhouse Effect

Some solar Some of the infrared radiation passes through radiation is the atmosphere, and some is absorbed and reflected by re-emitted in all directions by greenhouse gas the earth and molecules. The effect of this is to warm the the atmosphere earth's surface and the lower atmosphere.

Solar radiation passes through the clear atmosphere

Most radiation is absorbed Infrared radiation by the earth's surface is emitted from the and warms it earth's surface

agriculture and land clearing - are increasing animal species and more people exposed to concentrations of greenhouse gases in the infectious diseases such as malaria. atmosphere. Since 1750, the amount of carbon dioxide in the atmosphere has risen 35%, Most greenhouse gases have a long lifetime and the current concentration is higher than in the atmosphere. This means that even with any time in at least the past 650,000 years. reductions in greenhouse gas emissions, there The level of nitrous oxide has also risen 17% would be a delay of several decades before and methane 151%. This has enhanced the those reductions have a signifi cant effect greenhouse effect by trapping more heat, on greenhouse gas levels in the atmosphere. leading to global warming. Recent studies indicate that no matter how quickly we act, we are already committed Scientists assert that there will be continued to additional global warming during the 21st warming and increases in sea levels with century of around 0.5°C and the subsequent signifi cant impacts on natural and human impacts that are likely to follow. systems. Globally, these impacts include coastal fl ooding; more heatwaves storms In response to this challenge, we need and droughts; less frost, snow and polar to do two things: start planning adaptation ice; more people at risk of food and water strategies to minimise those consequences, shortage; reduced habitat for many plant and and reduce greenhouse gas emissions to slow the rate of global climate change.

02 | NEW SOUTH WALES GOVERNMENT / CSIRO Sydney

In 2004, the CSIRO and the Bureau of The report predicted that by the year 2030: 2.0 Meteorology released a report on behalf of the NSW Government which looked at past • NSW is likely to become warmer than Climate and likely future changes to NSW’s climate. it was in around 1990 • There will be more hot days over 35oC Change The report found that between 1950–2003, and fewer frost days below 0oC NSW became 0.9°C warmer, with more hot • Annual rainfall is likely to decline days/nights and fewer cold days/nights. in New • Rainfall runoff and stream ﬂ ows Annual total rainfall declined by an average will be reduced South of 14 mm per decade, with the largest declines • Droughts are likely to become more severe in rainfall near the coast due to an increase Wales in El Niño years since the mid-1970s. Extreme • The risk of bushﬁ res is likely to increase daily rainfall intensity and frequency have also • Extreme rainfall may become more intense decreased throughout much of the State. in central and southeast NSW.

More detailed ﬁ ndings of the report are listed in Table 1 (below).

Table 1. Annual and Seasonal Climate Projections for New South Wales Season 2030 2070 • Warmer by +0.2– +2.1°C • Warmer by +0.7– +6.4°C Annual • Rainfall change of -13 – +7% • Rainfall change of -40 – +20% • Warmer by +0.2 – +2.3°C • Warmer by +0.7– +7.1°C Summer • Rainfall change of -13 – +13% • Rainfall change of -40 – +40% • Warmer by +0.2 – +1.9°C • Warmer by +0.7 – +5.6°C Autumn • Rainfall change of -13 – +13% • Rainfall change of -40 – +40% • Warmer by +0.2 – +2.3°C • Warmer by +0.7 – +5.6°C Winter • Rainfall change of -13 – +7% • Rainfall change of -40 – +20% • Warmer by +0.2 – +2.1°C • Warmer by +0.7 – +7.1°C Spring • Rainfall change of -20 – +7% • Rainfall change of -60 – +20%

The Sydney Metropolitan Catchments cover incorporates more than 70 harbour and ocean 3.0 1,840 square kilometres associated with the beaches, including the famous Bondi Beach. highest population density in Australia. As of The 2005 there were an estimated 4,254,894 people The important natural resources of the region living in the Sydney statistical division, and underpin signifi cant economic activity. The Sydney relatively rapid population growth makes the major industries in the region include fi nance, catchments one of the fastest growing areas in extractive and manufacturing industries, Metro Australia. The Sydney Metropolitan Catchments property development, tourism and recreation. include Sydney’s Northern Beaches, Sydney The region contains Australia’s most famous Catchments Harbour, and the Narrabeen Lakes Catchment waterway, Sydney Harbour, Australia’s to Turimetta Head, and extends south to the oldest national park as well as nationally and catchments of Botany Bay and Port Hacking, internationally signifi cant wetlands. The region through the Royal National Park to Stanwell has a variety of landscapes including bushland, Park in the south. The region also extends foreshores, harbour areas and waterways, offshore three nautical miles. Sydney Metro’s market gardens, densely developed urban urban area covers 1,687 square kilometres and areas, industrial estates, drowned river valleys,

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sheer coastal cliffs and sand dunes. Signiﬁ cant sites and acid sulphate soils, and balancing surface water and ground water challenges environmental concerns with continuing include the sustainable management and development. Sydney is one of the most use of valuable ground and surface water diverse areas of NSW in terms of the plants resources, the management of stormwater and animals that are found there. However, quality and the management of harbour this biodiversity is under intense pressure. and river sedimentation. Land use also poses challenges such as managing contaminated

Summers in the Sydney Metropolitan Catchments are relatively warm, with average maximum January 3.1 temperatures of approximately 26°C (Table 2). However, the catchments do experience approximately 3 days above 35ºC each year. Winters are cool to mild, with average maximum July temperatures of 17°C. The Temperatures rarely fall below 0°C. The catchments receive approximately 1,100 mm of rainfall each year. Peak precipitation occurs between January and March, and the variability in rainfall from one year Climate to the next is high. Hail storms are common, the worst being the April 1999 event which cost $2.3 billion of the (IDRO, 2006). Bushﬁ res are also common, often occurring near residential properties. A warming of 1.0°C and a 5% decrease in rainfall (a moderate Sydney scenario for 2030) would make the climate of Sydney similar Metro to the current climate of Paterson to the north west of Newcastle. Figure 2. Climate Projections for New South Wales Catchments (The coloured bars show the range of projected changes corresponding with the colours in the maps)

Annual 2030 Annual 2030

Summer Summer

012345678 -60 -40 -20 0 20 40 60 Temperature Change (oC) Rainfall Change (%) Autumn 2070 Autumn 2070

Winter Winter

Spring 012345678 Spring -60 -40 -20 0 20 40 60 Temperature Change (oC) Rainfall Change (%)

Since 1950, the region has experienced warming and ﬁ re risk. Nevertheless, despite this trend of around 0.8ºC. This is likely to be partly due toward drier conditions, the possibility of to human activities. The catchments have also increases in extreme rainfall events remains. experienced a signiﬁ cant drop in annual rainfall Further details about these changes are at a rate of approximately 55 mm per decade. described in the following table (Table 2), which The contribution of human activities to this compares average conditions for the present rainfall decline is hard to distinguish from climate with ranges of potential change in 2030 natural variability. and 2070. These projections account for a broad range of assumptions about future global The future climate of the Sydney Metropolitan greenhouse gas emissions, as well as differences Catchments is likely to be warmer and drier in how various climate models represent the (Figure 2). Such trends would also increase climate system. evaporation, heat waves, extreme winds

04 | NEW SOUTH WALES GOVERNMENT / CSIRO Sydney

Table 2. Current and Projected Climate Change in the Sydney Catchment Present (1990) Projected Change 2030 2070 Temperature Average 17 – 26°C2 +0.2 – +1.6°C +0.7 – +4.8°C No. Days below 000 0°C No. Days above 3 4 – 6 4 – 18 35°C No. Days above 0 0 – 1 1 – 4 40°C Rainfall Annual Average 1,094 mm -13 – +7% -40 – +20% Extreme Rainfall3 -3 – +12% -7 – +10% Evaporation +1 – +8% +2 – +24% No. Droughts per 3 2 – 5 1 – 9 decade4 Extreme Winds -5 – +8% -16 – +24% No. Fire Days5 9 9 – 11 10 – 15

1 Present day conditions for temperature and rainfall represent long-term averages from the Bureau of Meteorology. For extreme temperatures, the present average is based on 1964-2003. For fi re danger, the present average is based on 1974- 2003. For drought, the present average is for a period centred on 1990. 2 Range represents average July and January maximum temperature. 3 Defi ned as 1 in 40 year 1-day rainfall total. Values represent the range in seasonal projections from a limited set of climate models for central eastern NSW. However, given strong spatial gradients in extreme rainfall projections (see Hennessy et al., 2004b), these regional results may not be applicable for Sydney. 4 The values for drought represent average monthly drought frequencies, based upon the Bureau of Meteorology’s criteria for serious rainfall defi ciency (see also Burke et al., 2006). 5 Number of days annually with a “very high” or “extreme” fi re danger index. Changes are for 2020 and 2050, respectively, as in Hennessy et al. (2005). 3.2 Impacts of Climate Change Water Changes in rainfall and higher evaporation in the Sydney Metro rates are likely to lead to less water for streams and rivers in the Sydney Metropolitan Catchments Catchments, which will have downstream consequences for storages and place strains Although changes in average temperature, rainfall and evaporation will have on the catchments’s water resources. For long-term consequences for the catchments, the impacts of climate change example, due to recent trends toward reduced are more likely to be felt through extreme weather events. Projections suggest rainfall, as of August 2006, catchment storages there will be more hot days, bushfi res, droughts and intense storms. These at Woronora were at only 29% 1 of capacity. can all place human life, property and natural ecosystems at increased risk. In addition, much of Sydney Metro’s water Additional details regarding climate change impacts to various activities and resources are sourced from the neighbouring assets in the catchments are discussed below. 1. Data obtained from the Water Observation Network: http://wron.net.au/DemosII/DamData/DamMap.aspx

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Hawkesbury-Nepean Catchment, where a number of key hot days could damage crops. storages are also at less than 50% capacity. In fact, the main impacts of climate change on Sydney’s water supply may result Higher temperatures will lead to inadequate winter chilling from effects in upstream catchments. for some fruit trees, which may reduce fruit yield and quality (Hennessy and Clayton-Greene, 1995). It may become necessary Various studies of stream fl ows in NSW indicate that climate to consider low chill varieties and alternative management change is likely to reduce fl ows in the future (Hassall and options. However, higher temperatures are likely to reduce Associates, 1998; Jones and Page, 2001; Beare and Heaney, the risk of damaging winter frosts. The key consequence of 2002; Bates et al., 2003; Warner, 2003). Under the National Water climate change on farming will clearly be rainfall. Any reduction Initiative, the Commonwealth, State and Territory Governments in rainfall will place most farms under stress, particularly when have agreed that water users should bear the risk of such linked to higher temperatures. For dryland cropping, reductions reductions in water availability. Other modelling studies have in rainfall and increases in evaporation directly contribute to also indicated the potential for increased fl ooding in catchments reductions in soil moisture. Meanwhile, irrigated agriculture is upstream from Sydney (Schreider et al., 2000). likely to be affected by tighter constraints on water allocations possibly resulting in a more developed and competitive water Lower fl ows and higher temperatures may also reduce water market. In this sense, the unusually hot droughts of 2002/03 and quality within the catchments. For example, low fl ows, higher 2005/06 may be a sign of things to come. Furthermore, heavy temperatures and elevated nutrients create a more favourable rains and winds from storm events may also contribute to crop environment for potentially harmful algal blooms. Greater fi re damage and soil erosion. Indirect impacts due to changes in activity could contaminate water catchments with sediment and weeds, pests and international markets may also place farms ash. Salinity problems in the catchments may be exacerbated under stress. by changes in rainfall, temperature and stream fl ows (Beare and Heaney, 2002). In addition to effects on surface water, Biodiversity the quality of coastal groundwater aquifers may be adversely affected by rising sea levels and salt-water infi ltration. Decreases Changes to the climate will have signifi cant effects on the in runoff due to climate change may reduce the extent and catchment’s plants and animals. Currently, 149 species, nine function of freshwater wetlands, such as the internationally populations and 21 ecological communities (i.e., collections of recognised Towra Point Estuary wetlands and the Botany species or habitat) in the Sydnery Metropolitan Catchments are wetlands. classifi ed as threatened or endangered (DEC, 2006). Although current threats to the catchments’s biodiversity are largely a Farms product of historical land clearing, alterations of river fl ows and water extraction, climate change is likely to heighten the need Although much of the Sydney Metropolitan Catchments is for conservation efforts. devoted to economic enterprises other than agriculture, climate change may still have adverse effects on some of the The geographic distribution of a species is often defi ned by catchment’s small-scale cropping and horticulture activities. its ‘climate envelope,’ refl ecting species-specifi c tolerances to Furthermore, impacts on agricultural industries in the extremes of temperature and moisture. Climate change is likely catchments surrounding Sydney will have direct implications to drive changes in the distribution of some plant and animal for those within the Sydney Metropolitan Catchments. species, driving some species out of the catchments or enabling invaders to move in. Meanwhile, even those species capable The farmers of NSW have developed useful adaptation skills of coping with climate change alone may succumb to the that stand them in good stead for dealing with climate change, cumulative effects of multiple stressors. Despite such impacts, but they will need to plan for new climatic challenges and little is actually known regarding how climate change may affect opportunities. Climate change will have both positive and the catchments’s rich biodiversity or ecosystems, such as its negative impacts on the types of crops that can be grown and endangered coastal saltmarsh. agricultural productivity in NSW. For example, higher levels of carbon dioxide in the atmosphere are likely to increase plant Other risks to biodiversity in the Sydney Metropolitan growth, but the protein content of those plants is expected to Catchments include: be lower. Low to moderate warming will also help plant growth • Reductions in stream fl ows are likely to have a negative and extend growing seasons, but a rise in the number of very impact on aquatic biodiversity and wetland ecosystems.

06 | NEW SOUTH WALES GOVERNMENT / CSIRO Sydney

• Plants and animals may become ‘stranded’ in isolated thermal comfort at minimal cost, while potential increases in remnants of vegetation due to changing climate and extreme winds may necessitate more robust construction. continued development within the catchments. In addition, a study by Austroads (2004) concluded that climate change would contribute to increases in road maintenance costs • More frequent droughts and fi res are likely to increase in NSW of up to 25% by 2100, largely due to assumptions about stress on plants and animals. the effects of climate change and population growth on traffi c • Sea-level rise is likely to inundate coastal wetlands and volumes. alter the discharge of freshwater into estuaries, with potential adverse effects on coastal wetland habitat. Given increases in the intensity of the heaviest rainfall events, fl ash fl ooding and strains on water infrastructure such as Forests sewerage and drainage systems would rise, particularly in population centres. For example, a study by Minnery and Smith The forests, woodlands and natural vegetation of the Sydney (1996) found that climate change may double fl ood-related Metropolitan Catchments are a signifi cant asset that is managed damages in urban areas of NSW, although more recent modelling for biodiversity conservation, maintenance of water quality, suggests that extreme rainfall events along the NSW coastline recreation and other purposes. may decline, but increase further inland (Hennessy et al., 2004b). Preliminary research suggests that temperate tree species and Regardless of changes in such extremes, higher temperatures forests in Australia may increase in productivity with higher and lower average rainfall are likely to lead to increased pressure temperatures and increased concentrations of atmospheric on urban water and energy supplies, unless moderated by carbon dioxide. However, these benefi ts may be offset by demand management measures. For example, McDonald (2006) decreased rainfall, increased bushfi res and changes in pests. estimated that per capita water demand in Sydney would have Also the benefi t of higher carbon dioxide concentrations may be to decline by 54% by 2030 in order to remain within sustainable limited in the longer term by the availability of nutrients (Howden yields. Higher temperatures would increase summer peak et al., 1999c). energy demand for air-conditioning (Howden and Crimp, 2001), increasing the risk of black-outs. Furthermore, climate change is likely to lead to changes in the distributions of tree species, possible increased invasion by pests, Modelling of weather patterns along the NSW coast indicates and changes to the habitat that these areas provide for local the potential for increases in the frequency of weather events plants and animals. This will raise new challenges in managing that contribute to extreme winds and, subsequently, storm trees and forest areas for biodiversity conservation and public surges (Hennessy et al., 2004b). Such increases in storm surge, in amenity. conjunction with future sea-level rise, would increase the risk of coastal inundation, erosion, and damage to infrastructure and Communities property. Cowell et al. (2006) estimated median erosion at Manly Beach from sea-level rise of 33.2 metres (±90 metres) by 2100. Warmer winters are likely to reduce cold-related illnesses, but Given a sea-level rise of 20 cm by 2050, coastal erosion of up to warmer summers are likely to increase the risk of heat-related 22 metres is projected for Collaroy/Narabeen beach, rising to 110 health problems, especially in the elderly (McMichael, 2003). metres given a 1 in 50 year storm surge, with associated economic For example, climate change and population growth and ageing losses of $230 million. may increase annual heat-related deaths in those aged over 65 in Sydney from 176 at present, to 364–417 by the year 2020 , and The risk of property loss due to bushfi re is also likely to increase. 717–1,312 by 2050 (McMichael et al., 2003). Warmer temperatures For example, on average Sydney is likely to experience 0–2 more may also contribute to the spread of infectious diseases, although days with a fi re danger index of “very high” or “extreme” by 2020 the spread of tropical diseases such as dengue fever into the and 1–6 more days by 2050 (Hennessy et al., 2005; see Table Sydney Metropolitan Catchments remains unlikely. 2). Given the large number of properties in bushland and the exposure of critical infrastructure, this would pose challenges for The built environment is also vulnerable to climate change. emergency management. As a consequence of these and other As well as impacting on homes, it will affect infrastructure, changes in extremes, such as winds and fl oods, insurance risk commercial buildings and other physical assets. Changes in assessments and premiums are likely to be affected. average climate will affect building design and performance, including structural standards and cooling and heating demand (PIA, 2004). Higher summer temperatures, for example, may induce a revaluation of building design and standards to ensure

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• Improving water-use effi ciency, recycling 4.0 and public education about water usage. • Enhancing water supplies through Adapting to Climate Change groundwater extractions and desalination, subject to environmental impact Adaptation is a risk management strategy assessments. involving actions to reduce the negative • Implementing early-warming and public impacts of climate change and take advantage communication systems for heat waves. of new opportunities that may arise. The types of adaptation measures adopted will • Designing energy effi cient buildings. vary from region-to-region. Because some of • Retrofi tting old, and designing new, the decisions we make today will have lasting infrastructure to cope with climate change. implications for future climate vulnerability, we must start planning our adaptive responses • Reviewing fl ood and fi re management now. By doing so, we may help to lessen some arrangements. of the environmental, economic and social • Reviewing coastal zone management costs of climate change. practices.

Some examples of potential adaptation • Maintaining green spaces and ecological measures relevant to the Sydney refugia in urban areas. Metropolitan Catchments include: Making sure the catchment has the necessary capacity to implement such adaptation measures means continually expanding 4.1 research, education and communication. Adaptation in Action

Throughout much of Australia, users of the land Some of the observed trends included: have developed considerable experience in • Solid understanding of local climate history managing the high degree of variability that is as the basis for greater understanding of characteristic of Australia’s climate. However, climate variability and change. many individuals and enterprises are recognising • Growing use of weather and climate that they are contending not just with climate websites for both long and short-term variability, but also climate change – and the forecasts. past is no longer a reliable indicator of future • The application of sophisticated tools (such conditions. In response, a broad range of as software for tracking sub-soil moisture adaptation actions are being implemented across and wheat yields) for making full use of all Australia. available moisture. • Shifts in the nature of crops and stock run In 1999, the Masters of the Climate project on the properties, with a movement away collected information from more than 80 from riskier varieties and activities. landholders on how they were using climate tools • Opportunistic decision-making – being to better manage their land resources and farm ready to act on short notice to take businesses – 23 were selected as case studies. advantage of weather conditions. In 2004, those 23 landowners were visited again • In a few cases, deciding to leave the to see how they fared during the 2002/03 drought enterprise altogether. and to identify trends in the use of climate tools All of the Masters of the Climate case over the intervening ﬁ ve years. studies from 1999 and 2004 are available over the internet at www.managingclimate. gov.au/information_resources.asp.

08 | NEW SOUTH WALES GOVERNMENT / CSIRO Sydney

5.0 What is the New South Wales Government Doing? The NSW Government is taking a leadership role in the management of climate change. In late 2005 the NSW Greenhouse Plan was released, which outlines the NSW Government’s response to climate change.

The NSW Greenhouse Plan outlines polices and actions in three main areas: • Awareness Raising • Adapting to Climate Change • Reducing Greenhouse Gas Emissions. Copies of the Plan can be downloaded from www.greenhouse nsw.gov.au. 6.0 What’s happening in the Sydney Metro Catchments? The following activities are currently underway within the link between water consumption patterns and an increased the Sydney Metropolitan Catchments with the goal of number of hot days. improving knowledge about climate variability and change • The NSW Government’s CCIARP is supporting research in the catchments, and adaptation options to reduce the within the NSW Department of Environment and Conservation catchments’s vulnerability: to quantify changes in fi re regimes from projected climate • The Upper Parramatta River Catchment Trust is coordinating change in the Sydney Metropolitan Catchments, and risks to a $1 million, 3-year study by CSIRO called Climate Change biodiversity, ecosystem functions, people and their property. Rainfall Extremes in Sydney and Region. It is developing fi ne • The NSW Government’s CCIARP is also supporting research spatial and temporal scale projections of rainfall intensities by the Sydney Coastal Council Group (SCCG) to calculate under current climate and in 2030 and 2070 for coastal the value of selected beaches in the Sydney metropolitan NSW, from Taree to Nowra. The local partners and fi nancial region, which will also help governments make more informed contributors are the Upper Parramatta River Catchment decisions on how to protect ‘at risk’ coastal property, Trust, Australian Greenhouse Offi ce, Sydney Metropolitan infrastructure, beach environments and amenity as a result Catchment Management Authority, Southern Rivers of inevitable and immediate coastal erosion risk. Catchment Management Authority, Hunter Central Rivers Catchment Management Authority, and Sydney Water. Other • SCCG is collaborating with CSIRO to study the implications agencies on the study Steering Committee are the NSW of climate change on the fi fteen member councils and evaluate Greenhouse Offi ce, Metropolitan Water Directorate, Sydney challenges and opportunities for pursuing adaptive decision- Catchment Management Authority and NSW Dept of Natural making on climate change at the scale of local government. Resources. • The University of New South Wales, in collaboration with the • The NSW Government’s Climate Change Impacts and Sydney Metropolitan Catchment Authority, is undertaking a Adaptation Research Program (CCIARP) is supporting study to downscale the global and regional climate models to a collaborative research effort to assess the impacts of the scale of Sydney’s water supply catchment. The modelled climate change on water supply and demand in the Sydney catchment scale rainfall projections will subsequently be Metropolitan Catchments. Of particular relevance to the translated into runoff projections and will provide an indication Sydney Metropolitan Catchments is an examination of the of future changes in catchment yields under different impacts of climate change on demand measures implemented greenhouse gas emission levels. to improve water use effi ciency. This includes investigation of

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