3.1 Greenhouse gas emissions and climate change

Total NSW greenhouse gas emissions in 2004 were 1% below 1990 levels; however, there has been a trend of increasing emissions since the first SoE in 1993. Unless there are significant behavioural changes, total emissions are predicted to continue rising, influenced by growth in emissions from the stationary energy sector. Increases in atmospheric concentrations of greenhouse gases are contributing to climate change.

Human activities such as the combustion of fossil fuels and land clearing are increasing the atmospheric concentration of greenhouse gases. Scientists conclude that this is very likely to be altering the overall heat balance of the atmosphere, leading to a rise in average global temperatures.

For NSW, scientists project a warming of between 0.2ºC and 2.1ºC over the next three decades, and a general tendency for decreasing annual average rainfall. Although some agricultural or forestry activities may benefit from small increases in temperature and carbon dioxide concentration, most changes in climate are expected to have negative impacts on natural ecosystems, water resources, primary industries, human health and settlements.

Per capita greenhouse gas emissions in NSW are lower than in some other Australian states. Per capita emissions have decreased by 15% since 1990 and are projected to remain stable for the next five years. NSW emissions per unit of economic output have also fallen by 33% since 1990.

The NSW Government has committed to ambitious, economy-wide long-term reduction targets: the return to year 2000 greenhouse emission levels by 2025, and a 60% cut in greenhouse emissions by 2050.

NSW indicators

Introduction

The Earth's climate is controlled by energy from the sun, which is absorbed primarily at the Earth's surface. So-called 'greenhouse' gases in the atmosphere, such as carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O), trap some of the energy re-emitted as infrared radiation from the surface, retaining heat and causing the surface to be warmer than it would otherwise be. This natural greenhouse effect is a key element in maintaining the Earth's average temperature at around 15^oC. Without this natural protection, the temperature would be around –18^oC.

Current status and trends

Up until the Industrial Revolution (about 1760), the Earth's temperature varied in cycles closely following the atmospheric concentration of carbon dioxide (Figure 3.1). The Industrial Revolution brought increased burning of fossil fuels such as coal, oil and gas (see Human Settlement 2.3) and widespread clearing of vegetation (see Biodiversity 6.1), which led to increased emissions of greenhouse gases, most notably carbon dioxide (NSW Government 2005). Since 1760, the atmospheric concentration of carbon dioxide has increased by 35% to about 375 parts per million (ppm) by volume (Figure 3.1) and is now the highest it has been for 650,000 years (Siegenthaler et al. 2005). Concentrations of other greenhouse gases have also risen since the Industrial Revolution – methaneby 151%, tropospheric ozone by 36%, and nitrous oxide by 17%.

Figure 3.1: Global carbon dioxide concentrations from Antarctic ice cores and global temperatures

Source: Etheridge et al. 1996; Petit et al. 1999; Flückiger et al. 2002; Carbon Dioxide Information Analysis Center data 2005.

Notes: Changes in temperature (red) and carbon dioxide concentrations (green) over the past 420,000 years are derived from bubbles of air trapped in polar ice. The carbon dioxide and corresponding temperature data for the period from 420,000 to 1500 years before 2005 is derived from the Vostok ice core in East Antarctica. More recent carbon dioxide measurements were obtained from the Dome C and Law Dome ice cores in Antarctica. No corresponding temperature data is available. The most recent data, obtained from the Carbon Dioxide Information Analysis Center, shows direct observations of greenhouse gases as measured at the Cape Grim Baseline Atmospheric Program in north-west Tasmania.

The World Meteorological Organization and the United Nations Environment Program have established the Intergovernmental Panel on Climate Change (IPCC) to assess scientific, technical and socio-economic information for understanding climate change. In their Third Assessment Report (TAR), the IPCC has concluded that there is an increasing body of evidence that human activities which increase greenhouse gas concentrations are 'enhancing' the natural greenhouse effect and resulting in a changing climate (IPCC 2001) (the enhanced greenhouse effect).

The IPCC has documented many observed changes in the Earth's atmosphere, climate and biophysical systems, for instance:

• the average atmospheric concentrations of the greenhouse gases carbon dioxide, methane and nitrous oxide have increased in the last 250 years
• average global mean surface temperatures have very likely risen by around 0.6^oC over the past century; the 1990s was the warmest decade since direct measurement records began in 1856 and is likely to have been the warmest decade of the millennium
• heavy rainfall events are likely to have increased at some latitudes, while summer drying and the associated incidence of drought is likely to have increased in other areas
• global mean sea level increased over the 20th century, while significant decreases in Arctic sea-ice thickness and extent have been observed, along with a very likely decrease in global snow cover of around 10% since the 1960s.

Observational evidence has increased since the release of the TAR, and the imprint of greenhouse gases as the primary cause of the observed warming has also become clearer (Steffen 2006). The atmospheric concentration of carbon dioxide continues to increase and the instrumental record showing a warming Earth is supported by satellite measurements of tropospheric warming and by observations at the Earth's surface (Steffen 2006). The accuracy of records of temperature change over the past 2000 years has improved, strengthening the argument that the current warming trend is beyond natural variability (Steffen 2006). These global changes are already affecting the natural environment. There have been observed changes to the growing seasons of plants, and to the breeding behaviour and geographic ranges of different species, as well as a decline in some plant and animal populations because of extremes in temperature or other climatic factors. These global trends have been mirrored in Australia, where average temperatures have increased by about 0.7°C since 1910 (AGO 2003) and 2005 was our warmest year on record (BoM 2006). Precipitation along Australia's east coast has declined steadily since the mid-20th century, while extreme rainfall events have increased in frequency, particularly during winter (AGO 2003; Preston & Jones 2006).

Projected climate change

By the year 2100, global average temperatures are projected to rise by between 1.4°C and 5.8°C, and sea levels are projected to rise by between 9 and 88 centimetres, relative to 1990 levels (IPCC 2001).These predictions are uncertain because of both the complexities of modelling environmental responses on such a vast scale, and the uncertainty in predicting how human populations will meet their energy needs so far into the future. However, since the release of the IPCC TAR, research has yielded a better understanding of three additional effects that are important for future climate projections: the radiative properties of aerosols, the reflectivity of the Earth's surface, and terrestrial carbon cycle dynamics (Steffen 2006). These all operate to amplify greenhouse warming, and there is now perceived to be a greater risk that the upper end of the IPCC estimated temperature rise will be reached or exceeded by 2100 (Steffen 2006).

A global average temperature change of 5°C is equivalent to those seen in the glacial–interglacial cycles known to have occurred over the past few million years. Such temperature differences between the peak of an ice age and current conditions have been associated with massive changes in global ice extent, sea-level changes of 100–200 metres, and radical variations in ecosystem distribution and composition. Projections of climate change in NSW, undertaken by CSIRO and the Bureau of Meteorology (CSIRO & BoM 2004), concluded that without action to limit emissions NSW could experience:

• a warming of between 0.2ºC and 2.1ºC over the next three decades (with the greatest rise in spring and summer) and a warming of between 0.7ºC and 6.4ºC by 2070 (see Figure 3.2)
• a general tendency for decreasing annual average rainfall, particularly in spring and particularly in south-western NSW (see Figure 3.2).

Figure 3.2: Projected changes in temperature and rainfall for NSW for 2030 and 2070 under two emissions scenarios

Source: CSIRO & BoM 2004

Notes: The diagrams show projected changes to average temperatures and rainfall for the years 2030 and 2070 (relative to 1990) for two different scenarios of global emissions. The IPCC 'business-as-usual' scenario includes anticipated technological advances but excludes deliberate actions to reduce greenhouse gas emissions. The '450 ppm' scenario shows the effect of global action to stabilise atmospheric concentrations of CO₂ at 450 ppm by the year 2090. The coloured bars show the intensity of change expected, and the corresponding colours on each map show where those changes are expected to occur.

The pattern of change across NSW is the same in each scenario, but the intensity of the change is much less under the '450 ppm' scenario. From the bar charts, the upper limit of warming or rainfall change by 2070 is reduced by about 48% if CO₂ concentrations are stabilised at 450 ppm by the year 2090.

While much of NSW shows a tendency for drier conditions, heavy rainstorms may become more intense and more frequent and other extreme weather events may also become more frequent. Under the worst-case scenario, with high levels of global warming, there may be a 70% increase in drought frequency by 2030, with twice as many days above 35°C by 2030 and six times as many by 2070. For western towns like Cobar, the number of days over 40°C could more than double (from six to 15) by 2030 (CSIRO & BoM 2004).

Impacts of climate change

Although in parts of NSW some agricultural or forestry activities may benefit from small increases in temperature and carbon dioxide, most changes in climate are expected to have negative impacts on natural ecosystems, water resources, primary industries, human health and settlements (AGO 2003).

Hotter, drier conditions could put crops under greater heat and water stress. Rivers are likely to decline, making irrigation less reliable and leading to the loss of wetlands. Climate change will be apparent in parameters such as temperature, rainfall, the Southern Oscillation Index and the associated occurrences of El Niño and La Niña episodes, which cause severe droughts and flooding in eastern Australia (see Toward Environmental Sustainability 1.1 and Appendix 1).

CSIRO projections for some climate-change scenarios show the snowfields largely disappearing by 2050, with serious implications for tourism, snow-fed water supplies for agricultural production, and other fundamental changes to the ecology of alpine areas (CSIRO 2003a), such as reduced habitat for species like the mountain pygmy possum.

Major storms may become more common over much of NSW, with the potential to damage buildings, bridges and power lines. In the coastal zone, these storms may combine with sea level rises to increase the risk of coastal erosion, with increased damage to beaches and waterside property. Bushfires are likely to become more frequent and intense, altering some plant and animal communities and increasing the risk to homes near bushland. Human health also faces risks as warmer temperatures increase the risk of infectious diseases, heat stress, food poisoning and mosquito-borne diseases.

Climate change associated with increased concentrations of greenhouse gases also acts to cool the stratosphere, which may slow the recovery of the ozone layer (Fraser 2003) creating further risk to human health from increased ultraviolet (UV) radiation (see Atmosphere 3.2).

Greenhouse gas emissions

NSW has around 33% of Australia's population of 20.4 million (ABS 2005) (see Human Settlement 2.1) but is responsible for only 28% of Australia's emissions. This disparity is because NSW has lower industrial emissions on a per capita basis than other Australian states. In 2004, total NSW emissions were 23.6 tonnes per person – high compared to the average of about 13 tonnes for industrialised nations, and more than double that of the UK, Germany and Japan (which each emit just over 10 tonnes per person).

NSW's comparatively high per capita emissions result from a high dependence on coal-fired power generation, the energy intensity of our exports (such as aluminium and steel), and long transport routes combined with a preference for road transport over rail (see Human Settlement 2.3 and Human Settlement 2.4).

Figure 3.3 summarises the most recent data from the NSW greenhouse gas inventory (AGO 2006a). In 2004, total NSW emissions were the equivalent of 158.7 million tonnes of carbon dioxide. Stationary energy is responsible for almost half of NSW emissions, with other key sources including transport (14%) and natural resource management (17%).

Figure 3.3: NSW greenhouse gas emissions for 2004 and emission sources by sector (million tonnes CO₂-e)

Source: AGO 2006a, AGO 2006b

Notes: Stationary energy emissions include fossil fuel combustion in electricity and heat production, and manufacturing and construction industries.
Transport emissions include those from road (cars, buses and trucks), rail, shipping and aviation, for both passengers and freight.
Industry and waste emissions include by-products of manufacturing processes for metal and chemicals, emissions from the decay of municipal waste, and fugitive emissions released during the extraction and production of coal, oil and gas.
Natural resource management emissions include agricultural emissions from livestock (methane produced during digestion), manure management, soils and burning of savanna and residues, and emissions associated with land-use change and forestry, such as forest management, tree planting and vegetation clearance.

Emission trends

Each greenhouse gas traps different amounts of heat, and their overall impact is expressed as an equivalent amount of carbon dioxide (CO₂-e). In 1990, NSW emissions were 160.6 million tonnes CO₂-e. Emissions declined almost 5% to 152.7 million tonnes in 1995, largely as a result of falling emissions from reduced land clearing during that period (Figure 3.4). However, underlying growth in the energy and transport sectors has contributed to an increase in total emissions by around 4% to 158.7 million tonnes in 2004, 1% below 1990 levels.

Historically, the growth in emissions has generally followed the trend of economic progress (see Human Settlement 2.3). However, the rate of emissions growth is now slowing compared to the rate of economic growth. Although total emissions continue to rise, NSW emissions per unit of economic output have fallen by about 33% since 1990. Annual NSW per capita greenhouse gas emissions also fell by 15% between 1990 and 2004, and are projected to remain stable during the next five years.

Projections of future emissions under 'business-as-usual' scenario in NSW to 2020, based on current trends and with existing policy measures, are shown in Figure 3.4. These are based on an analysis that draws from the National Greenhouse Gas Inventory and Commonwealth projections. The magnitude of the challenge ahead is demonstrated by the overall increase in emissions. Emissions from energy generation are expected to continue growing strongly, and are only partially offset by reductions in carbon dioxide emissions from tree planting and reduced land clearing.

Figure 3.4: Actual and projected greenhouse gas emissions under 'business-as-usual' scenario for NSW (million tonnes CO₂-e)

Source: NSW Greenhouse Office data 2006

Response to the issue

International and national response

International negotiations on a global framework for reducing emissions have been underway since the United Nations Framework Convention on Climate Change (UNFCCC) was first signed in 1992. The Australian Government ratified this convention in 1992.

One of the primary objectives of the UNFCCC is to stabilise greenhouse gas concentrations in the atmosphere at a level that would prevent 'dangerous' human interference with the climate system. This needs to be achieved within a time frame sufficient to allow ecosystems to adapt naturally to climate change, while ensuring that food production is not threatened and that economic development can proceed sustainably.

The Kyoto Protocol to the UNFCCC entered into force in 2005, and sets legally binding targets for industrialised countries to reduce emissions over the period 2008–12. The Australian Government has signed but not ratified the protocol, although it has indicated its intention to meet Australia's negotiated target of limiting emissions growth to 8% above 1990 levels. In 2005 Australia submitted its fourth National Communication on Climate Change (DEH 2005) to the UNFCCC, setting out the progress in implementing the country's international obligations to address climate change. The document outlines Australia's strategic framework of action, including policies and measures to enable Australia to meet its negotiated emissions target, as well as a framework for action over the longer term. Australia is currently on track to meet its emissions target (DEH 2005).

NSW response

In June 2005 the NSW Government committed to ambitious long-term reduction targets: the return to year 2000 greenhouse emission levels by 2025, and a 60% cut in greenhouse emissions by 2050. The NSW Greenhouse Plan (NSW Government 2005) sets out action for the NSW Government to reduce the emissions of its own activities and to work with other stakeholders to reduce emissions from their activities. The main objectives of the plan are to:

• increase awareness among those expected to be affected by the impacts of climate change
• begin to develop adaptation strategies to those climate change impacts we cannot avoid
• put NSW on track to meet its targets of limiting 2025 emissions to 2000 levels and reducing emissions by 60% by 2050.

The NSW Government had taken significant actions to reduce greenhouse gas emissions before the NSW Greenhouse Plan was released, including:

• the NSW Greenhouse Gas Abatement Scheme
• the Building Sustainability Index (BASIX)
• native vegetation reforms
• action plans and savings funds for energy and water.

The NSW Greenhouse Gas Abatement Scheme establishes a local market for emissions reductions and greenhouse credits (see Human Settlement 2.3). Under the scheme, electricity retailers must meet mandatory annual targets based on NSW per capita greenhouse emissions. Retailers can meet their targets directly or by buying credits that are created through:

• low-emission electricity generation (for example natural gas, solar, wind)
• activities that reduce demand and consumption of electricity
• carbon sequestration (the capture of carbon from the atmosphere in forests)
• activities by large users of electricity that improve the fuel efficiency of production or otherwise reduce onsite emissions.

The NSW Government has announced that the scheme will be extended until 2020 and beyond, or until a national emissions trading scheme has been implemented. The extension of the scheme will continue to provide a value in the market for greenhouse gas abatement projects in the event that there is a delay in agreement on a national scheme.

The Building Sustainability Index (BASIX) was introduced in 2004 and requires residential developments to achieve specific reductions in greenhouse gas emissions (see Human Settlement 2.1 and Human Settlement 2.3). It is estimated that BASIX will save 9.5 million tonnes of greenhouse gas emissions over 10 years.

Native vegetation reforms such as the Native Vegetation Act 2003 are expected to deliver a greenhouse benefit by ending broadscale clearing of vegetation (see Biodiversity 6.1). Greenhouse gas emissions in NSW from deforestation averaged 10.8 million tonnes per year between 1995 and 2001 (Australian Government 2005a). The vegetation reforms are expected to reduce emissions by a further 3.4 million tonnes per year by 2008.

Action plans and savings funds for energy and water introduce a requirement by the NSW Government for high users of water and energy, as well as government agencies and local councils, to prepare Savings Action Plans. These set out measures on how these organisations will save water and energy (see Human Settlement 2.2 and Human Settlement 2.3).

The NSW Greenhouse Plan outlines other key environmental initiatives, including:

• ongoing research into the impacts of climate change on bushfire risk; coastal erosion, storm surge and estuarine inundation; water supply and demand in GMR₂ (the greater metropolitan region comprising the Sydney, Illawarra and lower Hunter regions); biodiversity; weeds and pests in natural and agricultural systems; inland aquatic systems; and human health risks from climate change
• a plan for implementing the National Biodiversity and Climate Change Action Plan in NSW. Key adaptation strategies under this action plan include promoting ecological connectivity to aid migration and dispersal of species, protecting refuges, and creating specific management zones around important habitats.

Future directions

It is increasingly recognised that significant and sustainable global action will be required to forestall projected climate change trends and prevent large-scale damage to biodiversity, ecosystems and societies across the planet. Australia and NSW are not exempt from this process or its consequences, and climate changes based on current trends are likely to have significant adverse impacts for future generations of Australians. The response to climate change is likely to require substantial long-term cuts in greenhouse gas emissions in what is often referred to as a 'carbon constrained' future in which global emissions are regulated (NSW Government 2005). Reducing greenhouse gas emissions will require our energy supplies to come from cleaner sources, our energy consumption (including fuel for transport) to be reduced, and changes to some industrial, agricultural and land-use practices.

There are a significant number of Government initiatives in place to reduce greenhouse emissions; however, further action is required to achieve emission-reduction targets as part of a global effort to respond to climate change. Major policy initiatives are being developed at the state level, such as the national emissions trading system that the NSW Government is co-developing with other jurisdictions. By imposing a cost on emitting greenhouse gases, an emissions trading scheme creates incentives for the development and uptake of cleaner technologies and for behavioural change. A well-designed national scheme has the capacity to reduce emissions to meet target levels at the least overall cost to the economy.

NSW is fulfilling its role as a responsible member of the global community and is taking action to address climate change, both on its own and in collaboration with other jurisdictions.