New South Wales Climate Change Snapshot Overview of New South Wales Climate Change
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New South Wales Climate change snapshot Overview of New South Wales climate change According to long-term (1910–2013) observations, air temperatures have been increasing since the 1950s, with the highest temperatures on record being experienced in recent decades. The rate of change has also increased, with mean temperatures rising by 0.5°C per decade since 1990, compared to about 0.1°C per decade during the 1950s to 1980s. NSW is projected to continue to warm in the near future (2020–2039) and far future (2060–2079). The warming is projected to average about 0.7°C in the near future, increasing to about 2.1°C in the far future. There are not many differences across the state in the projected increases in average temperatures with all regions becoming warmer. The warming projected for NSW is large compared to natural variability in temperature. NSW currently experiences considerable rainfall variability across regions, seasons and from year-to-year and this variability is also reflected in the projections. Front cover photograph: Lookout at the evergreen eucalyptus valley between rocky ranges at The Blue Mountains in Australia. Copyright: Taras Vyshnya. Page 2: Wentworth waterfall, NSW, Australia. Copyright: Tomas Pavelka. Page 4: Manly Beach, NSW, Australia – Panoramic. Copyright: mingis. Page 11: Clyde River Bridge, Batemans Bay. Copyright: Christopher Meder. Page 15: Trees submerged in man- made lake, in glorious sunset light. Menindee, outback NSW, Australia. Copyright: Robyn Mackenzie. 2 Projected changes INCREASING ANNUAL INCREASING INCREASING INCREASING DECREASING DECREASING IN SPRING Projected temperature changes Maximum temperatures are projected to Maximum temperatures are projected to increase in the near future by 0.4 – 1.0°C increase in the far future by 1.8 – 2.6°C Minimum temperatures are projected to Minimum temperatures are projected to increase in the near future by 0.0 – 0.5°C increase in the far future by 1.4 – 2.6°C The number of hot days will increase The number of cold nights will decrease Projected rainfall changes Rainfall is projected to decrease Rainfall is projected to increase in spring and winter in summer and autumn Projected Forest Fire Danger Index (FFDI) changes Average fire weather is projected to Number of days with severe fire danger is increase in summer and spring projected to increase in summer and spring 3 Regional snapshots NSW and ACT Regional Climate the greater the confidence in the direction of change. Modelling project (NARCliM) In this report care should be taken when interpreting changes in rainfall that are presented as the average of The climate change projections in this snapshot are all of the climate change projections, especially when from the NSW and ACT Regional Climate Modelling the model outputs show changes of both wetting and (NARCliM) project. NARCliM is a multi-agency research drying. To understand the spread of potential changes partnership between the NSW and ACT governments in rainfall the bar charts should be considered along and the Climate Change Research Centre at the with the maps provided in this document. Help on University of NSW. NSW Government funding comes how to interpret the maps and graphs in this report is from the Office of Environment and Heritage (OEH), provided in Appendix 1. Sydney Catchment Authority, Sydney Water, Hunter Summary documents for each of the state planning Water, NSW Office of Water, Transport for NSW, and regions of NSW are available and provide climate the Department of Primary Industries. change information specific to each region. The NARCliM project has produced a suite of twelve The snapshots provide descriptions of climate change regional climate projections for south-east Australia projections for two future 20-year time periods: spanning the range of likely future changes in climate. 2020–2039 and 2060–2079. NARCliM is explicitly designed to sample a large range of possible future climates. 1. The climate projections for 2020–2039 Over 100 climate variables, including temperature, are described in the snapshots as rainfall and wind are available at fine resolution (10km NEAR FUTURE, or as 2030, the latter and hourly intervals). The data can be used in impacts representing the average for the 20- and adaptation research, and by local decision makers. The data is also available to the public and will year period. help to better understand possible changes in NSW 2. The climate projections for 2060–2079 climate. are described in the snapshots as Modelling overview FAR FUTURE, or as 2070, the latter representing the average of the 20-year The NARCliM modelling was mainly undertaken and period. supervised at the Climate Change Research Centre. NARCliM takes global climate model outputs and Further regional climate change information will be downscales these to provide finer, higher resolution released in 2015. climate projections for a range of meteorological variables. The NARCliM project design and the process for choosing climate models has been peer- reviewed and published in the international scientific literature (Evans et. al. 2014, Evans et. al. 2013, Evans et. al. 2012). Go to climatechange.environment.nsw.gov.au for more information on the modelling project and methods. Interpreting climate projections can be challenging due to the complexities of our climate systems. ‘Model agreement’, that is the number of models that agree on the direction of change (for example increasing or decreasing rainfall) is used to determine the confidence in the projected changes. The more models that agree, 4 Introduction This snapshot presents a summary of Population and settlements climate change projections for NSW. It NSW is Australia’s most populous state with over 73 outlines some key characteristics of the per cent of the NSW population living in major cities. state, including its current climate, before Between 1961 and 2011, the population of NSW detailing the projected changes to the almost doubled from 3.9 million to 7.2 million people. state’s climate in the near and far future. Population growth has been greatest in Metropolitan Sydney, as well as the Central Coast, Lower Hunter and Illawarra. Population growth has also been seen Topography and hydrography in coastal areas and in larger inland centres like Albury, Orange, Wagga Wagga and Tamworth (Department of Situated in the mid-latitudes of eastern Australia, NSW Planning & Environment 2014). covers an area of more than 800,000 km2, and has just over 2000 km of coastline. The state’s population is projected to reach 9.2 million people by 2031, with 64 per cent of this population The Great Dividing Range is an elevated region of (5.9 million), residing in Metropolitan Sydney. undulating terrain and broad plains which includes Population growth is projected to be larger in places the Snowy Mountains, with Mount Kosciuszko (2228 near Metropolitan Sydney, such as the Central Coast, m), Australia’s highest peak. The eastern side of the Wollongong, Newcastle and Port Stephens, coastal Great Dividing Range forms a steep escarpment with areas such as Tweed Heads and Port Macquarie, densely forested areas. The mountainous areas of areas to the north and east of Canberra and the ACT, the range and surrounding elevated areas include and regional centres such as Tamworth, Bathurst and the Southern Highlands, Central Tablelands and the Wagga Wagga (Department of Planning & Environment Northern Tablelands. The western side of the Range is 2014). less steep, ending in a series of hills and valleys which include much of the state’s fertile agricultural land. Natural ecosystems The western plains cover almost two-thirds of the state. These vast plains covered by riverine sediment The diversity of NSW landscapes is evident in the are almost entirely flat. wide variety seen in the state's bioregions. The Border Ranges of northern NSW is the most biologically The coastal rivers of NSW rise in the Great Dividing diverse area in the state and includes subtropical Range and flow eastwards to the sea. These rivers are rainforest, wet sclerophyll forest, mountain headlands, short, navigable at their lowest reaches and subject to rocky outcrops and transition zones between forests. flooding during high rainfall periods. The inland rivers The Brigalow Belt, located in inland northern NSW, rise on the other side of the range and flow westwards, is another important area for biodiversity. It has large with most of these rivers eventually combining into the tracts of eucalypt woodlands and is a stronghold for Murray–Darling River network which flows to the sea in endemic invertebrates. These two locations have South Australia. been identified on the list of Australia’s 15 National Biodiversity Hotspots1. 1. www.environment.gov.au/topics/biodiversity/biodiversity-conservation/biodiversity-hotspots/national-biodiversity-hotspots 5 Climate of NSW The climate of NSW is highly variable. Temperature The north-east of the state is dominated Cooler temperatures occur along the Great Dividing by summer rainfall, with relatively dry Range, with more moderate temperatures experienced winters. Conversely the south of the state along the coast. Temperatures get progressively experiences regular rainfall from cold hotter moving inland and towards the far north-west fronts and cut-off lows traversing south- of the state. Annual average temperatures (calculated from 1961-1990) range from about 4°C in the Snowy eastern Australia during the winter. Mountains to over 20°C in the far north-west and parts The coast of NSW is influenced by the warm waters of of the far north coast (Figure 1). the Tasman Sea, which moderate temperatures and In the summer, average temperatures range from provide moisture for abundant rainfall. Moist onshore 28–30°C in the state’s north-west to 10–12°C in the winds deposit considerable precipitation on the Snowy Mountains. In winter, average temperatures steeply rising terrain of the Great Dividing Range.