2.3 Climate change impacts and adaptation in NSW
According to climate change science, New South Wales will become hotter, there will be a shift in rainfall patterns and sea levels will rise. These changes will have an impact on the NSW economy, the health of the population, and the natural and built environment.
Climate change in NSW is likely to affect all regions, but to different extents. Biodiversity, the coastline, human health, infrastructure and agriculture will also be affected. Since some change is unavoidable, NSW needs to accelerate preparation to reduce future risk and exposure, including coordinating emergency response capabilities and ensuring the land-use planning system prepares us for future change. The NSW Government has an important role to play in leading and guiding adaptation responses, although partnership with local government, business and the community will be most effective in allowing the state to adapt to climate change.
The projected changes to the climate of NSW described in Climate Change 2.1 include rising sea levels, increased temperatures and changes to available water. These changes are likely to have a variety of implications for the state's environment, communities and economy. The frequency of extreme weather is projected to increase, with more coastal erosion and damage to infrastructure, and other climate change impacts will mean that biodiversity, human health, infrastructure and industries, such as tourism and agriculture, are affected.
Status and trends
Impacts of climate change
To better understand what the impacts of climate change signify, the NSW Government, in partnership with the Climate Change Research Centre at the University of NSW, has developed regional climate projections for NSW (see Climate Change 2.1). This work has used the same data sources as were used in 2007 by CSIRO and the Australian Bureau of Meteorology (CSIRO & BoM 2007), but the data was processed using innovative methods published in international literature. These projections have been used to assess the likely impacts of future climate change that NSW may face by 2050 (DECCW in prep.).
Extreme weather events, such as heatwaves and droughts, are projected to become more frequent (CSIRO & BoM 2007).
In lower parts of the coastal floodplains, the combination of rises in sea levels and catchment-driven flooding is 'likely' (>66% probability) to increase the height, extent and frequency of floods. Sea level rise is 'likely' to exacerbate the erosive effect of storms (DECCW in prep.).
Increases in temperature and evaporation will 'more likely than not' (>50% probability) lead to increased fire frequency across NSW towards the year 2050. The frequency of days of very high or extreme fire risk is projected to increase by 10–50% in that period (DECCW in prep.) (see Biodiversity 7.6). Increased fire-weather risk resulting from climate change is projected to be highest in inland regions (Hennessy et al. 2005). In Sydney and the Blue Mountains, bushfires are likely to occur more frequently (up to 24% more fires) and be more extensive (up to a 35% larger area) as a result of climate change by 2050 (Pitman et al. 2007; Bradstock et al. 2008).
The costs of extreme weather events are significant: of the top 20 insurance losses in Australia to April 2006, all but one relate to extreme weather events, such as hailstorms, cyclones, bushfires and floods. Of the top 20, nine of the most costly events were in Sydney and included hailstorms, floods and wind damage, with the 1999 hailstorm in densely populated areas of Sydney resulting in the largest insurance payout in Australian history (PMSEIC Working Group 2007). It should be noted that the science is uncertain as to whether there will be an increase in hailstorm frequency and intensity in NSW as a result of climate change (Niall & Walsh 2005; Leslie et al. 2007).
Natural systems are sensitive to changes in climate, and many plant and animal species respond to changes in climatic variables, such as temperature, rainfall and humidity. Observations of range shifts for species, along with changes in the timing of life cycles, are among the best-documented of recent impacts which have been linked to a climate signal (Hughes 2000; Walther et al. 2002; Hughes 2003a; Hughes 2003b; Parmesan & Yohe 2003; Parmesan 2006) (see Biodiversity 7.2). Examples of some observed changes in species in Australia consistent with climate change include:
- native and feral animals from lower elevations colonising alpine ecosystems (Green 2003; Pickering et al. 2004)
- snow gums (Eucalyptus pauciflora) encroaching into subalpine grasslands at higher elevations (Wearne & Morgan 2001)
- sleepy lizards (Tiliqua rugosa) changing their mating behaviour, with warmer and drier winters leading to earlier mating and longer pairings (Bull & Burzacott 2002).
Species and ecosystems may be able to adapt to climatic changes in a number of ways, through strategies such as:
- evolving or changing their behaviour in their current location
- taking refuge in local areas that are buffered from the changes
- migrating or dispersing to areas where the climate is more suitable.
However, these natural adaptive responses of native species and ecosystems may be constrained by both the increasing speed of the changes in climate and existing threats to biodiversity. Species and ecosystems currently under pressure from other threats including invasive species, drought and habitat loss are less likely to be resilient to changes in climate (DECCW in prep.).
Species identified most at risk from climate change include species with:
- a narrow range of physiological tolerances, low genetic variability and long generation times
- specialised requirements for other species or narrow geographic ranges
- limited capacity to disperse (move) to new habitats (Steffen et al. 2009).
Changes in climate may also result in new opportunities for the expansion of invasive species.
The impacts of climate change are projected to cause some significant loss of biodiversity around Australia (IPCC 2007b). Likely impacts on native species and ecosystems in NSW have been identified in the NSW Climate Impact Profile (DECCW in prep.) and include:
- changes in the composition and function of ecosystems through the loss of sensitive species and spread of generalist and invasive species
- changes in fire frequency and intensity which may lead to the loss of fire-sensitive species and changes in forest structure and composition
- rising sea levels resulting in saline intrusion and coastal recession which may eliminate some coastal ecosystems, affecting species such as shorebirds, waders and fish
- snow-dependent species and ecosystems and high-altitude ecosystems likely to contract or disappear altogether.
In the marine environment, carbon dioxide increases may lead to higher ocean acidity, while a rise in ocean temperatures could also lead to changes in marine pest distribution (Hobday et al. 2006) (see Water 6.5).
Coastal erosion and inundation
The NSW Government has adopted sea level rise benchmarks of 0.4 m by 2050 and 0.9 m by 2100 relative to 1990 sea levels for planning purposes (DECCW 2009a) (see also Climate Change 2.1). The NSW population is highly concentrated in coastal areas, which increases human susceptibility to sea level rise.
Sandy beaches are 'likely' (>66% probability) to recede by about 5–10 m for each 0.1 m of sea level rise, although this is dependent on local geomorphological and climatic conditions. Greater recession is possible in some locations. Erosive storms are 'likely' to become more frequent and, due to sea level rise, peak ocean water levels during storms are 'virtually certain' (>99% probability) to increase, producing more intense and frequent coastal inundation, higher wave run-up levels and water levels in lakes and estuaries and more flooding in the valleys of coastal rivers (DECCW in prep.). Extreme sea level events in Sydney Harbour are about three times more likely now than they were earlier in the last century (Church et al. 2006).
Tidal dynamics and tidal ranges in estuaries are also 'virtually certain' to change, with consequent impacts on conditions in entrance channels and the location of shoaling and erosion. It is 'virtually certain' that these changes will progressively damage existing low-lying coastal development and have an impact on existing infrastructure, warranting updates to development regulations (DECCW in prep.).
Coastal dunes are 'likely' to be threatened by erosion from a combination of sea level rise, changes in wave direction and increased storm intensity. Developed areas of the coast that have had natural dune systems removed and replaced with engineered walls may become exposed to water levels and dynamic wave forces beyond their original designs. A number of sites along the NSW coast already exhibit this coastal erosion threat (DECCW in prep.).
Sheet, rill and gully erosion are 'likely' to increase and an increased risk of mass soil movement is 'likely' on all currently vulnerable slopes in coastal hinterlands, due to projected increases in rainfall intensities (DECCW in prep.).
Australia's water resources are particularly vulnerable to climate change as Australia is the driest permanently inhabited continent on Earth (see Water 6.1). In NSW, rainfall is projected to decline in the south and west of the state (see Climate Change 2.1). This means that there may be significantly reduced runoff to the catchments to supply water storage and irrigation systems as well as sustain the natural environment.
It has been observed in water catchments throughout Australia that decreased rainfall results in an even larger proportional decline in inflows to the water supply system, and the relative proportion of inflow decline rises as drier conditions persist (CSIRO & BoM 2007). The median or best estimate of the likely trend between 1990 and 2050 in mean annual runoff for the whole of NSW (and the Australian Capital Territory) is a 5% decrease. Runoff is projected to decrease in the south and increase in the north-west (DECCW in prep.).
The greatest impacts in NSW associated with changes in water availability are likely to be seen in the Murray–Darling Basin. A recent CSIRO analysis found that surface water availability across the Murray–Darling Basin is expected to fall by more than 10% by 2030 (CSIRO 2008b).
With the increased temperatures projected due to climate change, the associated reduction in snow cover will have impacts not only on the ecology of the alpine zone but also on the seasonality and quantity of flow of water into the Murray River (DECCW in prep.). Declining rainfall and overuse of water in the Murray–Darling Basin is also leading to a decline in water quality, which poses a threat to the communities which rely on the system for drinking water and a threat to irrigation. There is a 50% chance that by 2020 the Murray–Darling system will reach a salinity level which exceeds the desirable limits for drinking water and irrigation (PMSEIC Working Group 2007).
Agriculture, fisheries and forestry
Climate is likely to have implications for agriculture and food production in NSW due to changes such as increased frequency of drought and declining water availability. This is a major threat to the NSW economy, of which agriculture is an important component valued at $9 billion in 2007–08 (ABS 2009).
Crops that are dependent on irrigation are likely to be severely restricted in some years by limited water availability. In addition, increased temperatures can mean that crops require more water to grow, which results in declining yield per unit of water available, whether in a drought year or not (CSIRO & BoM 2007). Temperature changes may alter the planting window and length of the growing season, requiring changes to traditional cropping and farming practices, particularly for summer crops (DPI 2007). Increased heat and weather damage will also affect fruit and vegetable production. Conversely, with higher atmospheric carbon dioxide concentrations, crops will use water more efficiently and this may counteract some of the negative impacts of increased temperatures.
The higher risk of bushfire and possible increase in the impacts of pests and disease is very likely to threaten some primary industries, such as forestry, horticulture and grazing (DPI 2007).
Livestock within agricultural industries are likely to suffer increasing heat stress, which will affect growth rates, egg and milk production, and reproduction. Rising sea levels, storms, reduced stream flow, ocean acidity and salt water incursion into estuaries are likely to reduce or alter fish stocks (DPI 2007) (see Water 6.5).
The NSW population is highly concentrated in coastal areas, which increases its susceptibility to sea level rise. Sea level rise is 'virtually certain' (>99% probability) to threaten low-lying developments along the coast (DECCW in prep.), with increased impacts on relief organisations, emergency services, and insurance premiums and insurability.
Climate change is expected to alter the nature of extreme storm events. An increase in the number of intense storms, or in the intensity of storms, would cause significant damage to coastal infrastructure including ports and harbours, airports, and storm water and sewer infrastructure (DECCW in prep.).
Low-lying developments along the NSW coast that are near current high-tide levels will be more susceptible to frequent tidal and stormwater inundation, and stormwater drainage is 'extremely likely' (>95%) to be less effective during high tides. Some settlements are already experiencing the effects of coastal erosion and the combination of sea level rise on these settlements would then have a significant impact on vulnerable infrastructure. The vulnerability of urban areas near coastal rivers, lakes and estuaries will be increased by the combined impact of marine and catchment flooding (DECCW in prep.).
Climate is a key factor that determines human health. Health risks from climate change are both direct (such as heatstroke) and indirect (such as mental health resulting from environmental, social and economic disruption in agricultural areas affected by drought).
Increases in temperature and more frequent and intense heat waves are the most likely and significant health impacts associated with climate change. In Australia, an estimated 1200 people die each year as a result of hot weather (Woodruff et al. 2007). While all people are vulnerable to heat-related illness, the elderly, babies and young children, people with chronic respiratory, cardiac or renal conditions, and people of low socioeconomic status are at greatest risk (DoH 2008; Heltberg et al. 2008).
Climate change may also affect air quality. Elevated temperatures may increase the generation of ozone, the principal component of photochemical smog (see Atmosphere 4.1). Modelling indicates an increase in the number of exceedences of the 1-hour ozone standard in the Sydney region of 27–30% by 2021–30 and 45–92% by 2051–60 (compared with the 1996–2005 period) (Cope et al. 2009). Changes to fire regimes may also increase atmospheric concentrations of fine particles.
In urban settings, high temperatures cause an increase in ozone which reduces air quality (see Atmosphere 4.1). The acute health impacts of poor air quality include respiratory illnesses, such as asthma, and eye, nose and throat irritation (Chen et al. 2007).
Increase in the frequency and intensity of drought and other natural disasters (including fire and flood) is likely to cause additional stress and impact on people's resilience, particularly in rural and remote areas that are more likely to be subject to a wider range and more intense climate change impacts. Increases in mental illnesses, such as depression and post-traumatic stress disorders, are likely as a result of the projected effects of climate change (Sartore et al. 2007; Hansen et al. 2008). There is a risk of more injuries associated with more frequent natural disasters, although this is yet to be quantified.
While health risks for water-, food- and vector-borne diseases may increase in northern parts of Australia as a result of climate change, there is no definitive evidence to support an increased risk in NSW (Russell 2009; Russell et al. 2009).
Anticipated changes in climate will have significant impacts on key features of the state's economy and way of life. In particular, changes will be required:
- in the use of low-lying coastal areas
- for agriculture in inland areas, especially in the south-west of NSW
- for activities that rely on snowfall.
Increased risks from bushfire will also need to be accommodated. Early implementation of adaptation measures to climate change has the potential to reduce costs in the future.
The NSW Government is developing a range of programs and policies to assist the state to prepare for the impacts of climate change. These focus on quantifying and locating the risks, then preparing suitable risk management and adaptation actions. This work will be ongoing, progressively informed by evolving science.
The Climate Change Action Plan is under development by the NSW Government. The action plan will outline how the NSW Government will prepare the state to adapt to the future impacts of climate change and continue the work of the NSW Greenhouse Plan.
The NSW Climate Impact Profile (DECCW in prep.) will provide extensive scientific modelling on the projected climate change impacts for NSW, supported by a series of regional impact profiles based on the NSW regions in State Plan 2006: A new direction for NSW (NSW Government 2006). The profile will outline some of the risks NSW may face under a changing climate to help state and regional decision-makers develop their planning and response strategies. To further understand what these impacts mean for the state, the NSW Government is developing a method for determining the vulnerability of NSW regions to climate change. These regional vulnerability assessments will be used to build community capacity to undertake adaptation planning for the region.
Climate Change Impacts and Adaptation Research Program: The NSW Government developed this program as part of the NSW Greenhouse Plan. The program, which ran from 2005 to 2009, analysed future climate impacts such as bushfire risk, sea level rise, invasive species, human health and metropolitan water supply. One project under the research program was a coastal mapping project using light detection and ranging (LiDAR) technology to identify low-lying areas on the Hunter and Central coasts at risk from sea level rise. Combining the three-dimensional model with existing data layers allowed an assessment of assets and land at risk under different climate change scenarios. This type of information is important for informing decisions made by councils, companies and individuals in low-lying areas.
NSW Sea Level Rise Policy Statement: The NSW Government has a long-term goal to see coastal communities adapt to rising sea levels in a manner that minimises the social disruption, economic costs and environmental impacts. To support sea level rise adaptation, the NSW Government has adopted the NSW Sea Level Rise Policy Statement (DECCW 2009a). This outlines proposed Government action on sea level rise adaptation and, as part of an adaptive risk-based approach, sea level rise benchmarks specific to NSW are included. The benchmarks are a sea level rise of 0.4 m by 2050 and 0.9 m by 2100 relative to 1990 mean sea levels. These benchmarks represent the NSW Government's guidance on sea level rise projections for land-use planning and coastal development decision-making. The benchmarks will ensure that developments accommodate the projected impacts of sea level rise on coastal hazards and flooding through appropriate site planning and design. The Government adopted the policy statement, following a period of public consultation.
Climate Change Science Research Network: The NSW Government established this network in 2008 to provide independent technical advice on climate change adaptation science and to help shape the Government's climate change science agenda. This network comprises leading academic researchers from a range of disciplines. Through this partnership the NSW Government is developing a collaborative research program to address gaps in regional information.
Statement of Intent for Anthropogenic Climate Change: Climate change is now listed as a key threatening process under the NSW Threatened Species Conservation Act 1995. The NSW Government is responding to this listing by preparing a Statement of Intent for Anthropogenic Climate Change, expected to be released in 2009–10. This statement will outline the actions that the Government will take over the next five years to reduce the negative impact of climate change on biodiversity.
Murray–Darling Basin reform: Through the Council of Australian Governments (COAG), major reforms to Murray–Darling Basin water management are under way, including the expenditure of more than $1 billion over 10 years to improve the efficiency and sustainability of water management. This will improve the resilience of the Murray–Darling Basin to climate change (see Water 6.1).
The 2006 Metropolitan Water Plan is the key tool for managing the impacts of current and future climate variability on water supply and demand in the metropolitan region to at least 2015 (see Human Settlement 3.1). It will be reviewed in 2010. The review will include factoring in new information about impacts of climate change.
The Snowy Mountains cloud seeding trial aims to determine the effectiveness of cloud seeding in increasing natural snowfall and inflows to storages of the Snowy Mountains Scheme. In 2008 the trial was expanded by increasing the target area by 1000 km2 to 2250 km2, and extended until 2014. If the expanded trial fulfils its potential, it is expected to have significant benefits for NSW and the Murray–Darling Basin.
Climate Risk Management Project: The NSW Government developed the Climate Risk Management Project in 2005 to assist farmers in adapting to climate change. Through this project the Government aims to raise awareness and build partnerships, provide an understanding of climate change and its potential impacts on agricultural production, and give farmers across all industries the capacity to start planning their strategies for adaptation. The Farmer's Guide to Managing Climate Risk is a course which is run as part of the program. Over 2008 and 2009 this course has been delivered at regional centres throughout NSW. The course guides farmers in the use of web-based decision-making tools and the use of weather information provided by the Bureau of Meteorology. Other educational and community programs are discussed in People and the Environment 1.5.
National Adaptation Framework: COAG requested the development of the framework in 2006 to act as the basis for government action on adaptation over the next five to seven years (COAG 2007). The framework, endorsed in 2007, sets the agenda for the federal and state governments on climate change adaptation. A key aspect of this agenda is to develop strategies for both the most vulnerable regions, such as the coast, and sectors, including agriculture, biodiversity, fisheries, forestry, settlements and infrastructure, water resources, tourism and health. The NSW Government has been working closely with the Australian Government on this framework.
The National Climate Change Adaptation Research Facility, which provides governments with robust and relevant information on climate change impacts, vulnerability and adaptation options, has been established under the National Adaptation Framework. The research facility also coordinates the development of National Adaptation Research Plans, which are important for collaboration and coordination of climate change adaptation research across Australia. They identify disparities in the information available to governments in vulnerable sectors and regions and set national research priorities.
Climate change is one of the most complex and pressing issues facing NSW, with the potential to significantly affect the environment, economy and communities. While the state will continue to look at ways to reduce emissions as part of a global effort to minimise the severity of climate change, some degree of change is now inevitable and further efforts should be directed towards prepartion for future changes.
An effective adaptation response will require continued investment in science and research to better understand regional impacts. As global climate data and modelling techniques improve, continued updates of regional analyses will further the understanding of how NSW may be affected by future climate change. It is important to appreciate not only how the climate will change, but also how changes will alter the environment and interact with other environmental, economic and social drivers. The impacts of climate change will vary across NSW and information will need to be collected for all regional, social and environmental systems.
While credible and effective responses to climate change should be based on current and reliable science, there will always be some uncertainty about the type, magnitude and rate of future changes and impacts. This uncertainty needs to be incorporated into flexible and responsive adaptation policies that focus on building the resilience and adaptive capacity of environmental, economic and social systems.
Climate change is a complex, multidisciplinary issue, and is likely to have implications for a range of sectors in NSW. While the NSW Government has an important role to play in leading and guiding adaptation responses, partnership between local governments, businesses and the community will be most effective in allowing the state to adapt to climate change.