CC3: Greenhouse gas emissions
By 2020, emissions from electricity generation will fall to zero and the ACT will meet the legislated target for total emissions. Transport will contribute over 60% of ACT’s emissions after 2020 and will become the main focus for future reductions. However, transport emissions increased by 13% between 2012–13 and 2017–18 and will represent a significant challenge in the future. The phasing out of natural gas will also be important. Per capita greenhouse gas emissions were just over 8 tonnes in 2017–18, a decrease of around 24% from 2012–13.
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Indicator assessment legend
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Environmental condition is healthy across the ACT, OR pressure likely to have negligible impact on environmental condition/human health.
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- Fair
- Good
Environmental condition is neither positive or negative and may be variable across the ACT, OR pressure likely to have limited impact on environmental condition/human health.
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- Fair
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Environmental condition is under significant stress, OR pressure likely to have significant impact on environmental condition/ human health.
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- Unknown
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Data is insufficient to make an assessment of status and trends.
Improving
Deteriorating
Stable
Unclear
Adequate high-quality evidence and high level of consensus
Limited evidence or limited consensus
Evidence and consensus too low to make an assessment
Assessments of status, trends and data quality are not appropriate for the indicator
Background
Greenhouse gas emissions from human activity have increased since the pre-industrial era, mainly through the combustion of fossil fuels and widespread land clearing, with emissions now higher than ever. This has led to atmospheric concentrations of carbon dioxide, methane and nitrous oxide that are unprecedented in at least the past 800,000 years. The high atmospheric concentrations of these gases have been the dominant cause of the observed changes to climate conditions since the mid–20th century.
Global efforts through the United Nations Framework Convention on Climate Change, including the Paris Agreement, aim to keep the global average temperature increase to well below 2 °C and to pursue efforts to keep warming to below 1.5 °C. Achieving this target will require a significant cut in global greenhouse gas emissions. This is dependent on both regional and local actions to reduce emissions. Whilst the ACT’s emissions are only a fraction of that produced globally, the effect of cumulative reductions from local actions across the world will make substantial contributions to minimising the severity of climate change in the future.
The ACT Government has legislated greenhouse gas emissions reduction targets under the Climate Change and Greenhouse Gas Reduction Act 2010. The legislated targets are for percentage reductions from 1990 levels and include:
- 40% reduction by 2020
- 50% to 60% reduction by 2025
- 65% to 75% reduction by 2030
- 90% to 95% reduction by 2040, and
- net zero emissions by 2045.
Greenhouse gas types and sources
The majority of greenhouse gas emissions come from energy, transport and industry. Those emitted by human activities and measured in the ACT are:
- carbon dioxide from burning fossil fuels (coal, natural gas and oil), solid waste, trees and wood products, and also as a result of certain chemical reactions (such as the manufacture of cement).
- methane emitted during the production and transport of coal, natural gas and oil, livestock and other agricultural practices, and from organic waste decay in municipal solid-waste landfills.
- nitrous oxide from the combustion of fossil fuels and solid waste, and also from agricultural and industrial activities, and
- fluorinated gases, including hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride and nitrogen trifluoride, which are synthetic gases that are emitted from a variety of industrial processes.
The combined effect of all greenhouse gases is expressed as the amount of warming that would be caused by an equivalent amount of carbon dioxide (CO2-e). It is important to note that each greenhouse gas has a different warming effect on the atmosphere. For example, 1 tonne of methane is expressed as 21 tonnes of CO2-e because over the span of 100 years methane will trap 21 times more heat than carbon dioxide. This means that small amounts of some gasses have a potent effect on our climate.
Condition and trends
Total emissions
In 2017–18, the ACT’s total greenhouse gas emissions were 3,368 thousand tonnes of CO2-e (Figure CC7). This was a 17% decrease on 2012–13 levels, but 5% higher than the 1989–90 levels that are used as the basis for the ACT’s emission reduction targets. Decreases in total emissions are the result of the growth in the ACT’s total renewable electricity generation, increasing from 20% of electricity supply in 2015–16 to nearly 50% in 2017–18 (see Indicator HS2: Energy consumption and generation).
By 2020, ACT’s renewable electricity is forecast to meet 100% of demand; as a result, greenhouse gas emissions from electricity generation will fall to zero. With the elimination of electricity emissions, the ACT’s total emissions are projected to decrease to around 1,918 thousand tonnes of CO2-e. This means that total greenhouse gas emissions for the ACT are expected to meet the legislated 2020 target – a 40% reduction on 1990 levels.
Figure CC7: Total ACT greenhouse gas emissions (CO2-e) 2012–13 to 2017–18 and projected emissions 2019–20.
Per capita emissions
The annual per capita greenhouse gas emissions for the ACT was just over 8 tonnes in 2017–18 (Figure CC8). Per capita emissions decreased by around 24% between 2012–13 and 2017–18, and by 29% compared to 1989–90 levels. This decrease has been important to offset annual population growth in the ACT (see section Population section in Human settlements).
Per capita emissions will drop significantly with the projected elimination of electricity emissions by 2020. However, beyond 2020 further decreases in per capita emissions will depend on reductions in other sectors such as transport.
The Climate Change and Greenhouse Gas Reduction Act 2010 introduced a legislated requirement for the ACT’s per capita emissions to peak in 2013 (compared to 1990 levels). This target has been met and per capita emissions have decreased since 2012–13.
Figure CC8: ACT annual per capita greenhouse gas emissions (CO2-e) 2012–13 to 2017–18.
Emissions by source
Between 2012–13 and 2017–18, the electricity generation and transport sectors were the dominant source of greenhouse gas emissions in the ACT (Figure CC9). Electricity accounted for 57% (2,295 thousand tonnes CO2-e) of total emissions in 2012–13, decreasing to 44% (1,468 thousand tonnes CO2-e) in 2017–18 as the share of renewable energy increased. With the ACT’s renewable electricity forecast to meet 100% of demand, the electricity sector will not contribute to the ACT’s emissions after 2020. Further reductions in emissions beyond 2020 will therefore focus on other sectors such as transport, industry, gas and waste.
Figure CC9: ACT greenhouse gas emissions (CO2-e) by source, 2012–13 to 2017–18.
Changes in the emissions of non-electricity sectors are shown in Figure CC10. Unlike the electricity sector, transport emissions are growing, both in terms of actual emissions and their proportional contribution to total emissions. Between 2012–13 and 2017–18, transport emissions increased from 1,017 thousand tonnes CO2-e to 1,147 thousand tonnes, an increase of 13%. This growth, combined with the decrease in electricity emissions, led to transport contributions increasing from 25% to 34% of total emissions in the ACT. This proportion is projected to increase to 62% in 2020.
The stationary gas sector contributed 11% of total emissions in 2017–18, with annual emissions fluctuating from year to year and no overall trend evident (most likely related to changes in annual usage due to weather conditions).
Industrial processes only contributed around 8% of total ACT emissions in 2017–18; however, emissions from this sector have increased by 31% since 2012–13. The waste sector contributed around 2% of total emissions in 2017–18, and is also highly variable due to the annual variation in waste produced (see Indicator HS3: Solid waste generation and management). ACT’s agriculture sector contributed less than 1% of total emissions in 2017–18.
Figure CC10: Main non-electricity sector sources of greenhouse gas emissions (CO2-e) in the ACT, 2012–13 to 2017–18.
Transport emissions and fuel type
With transport set to contribute 62% of total emissions by 2020, the current growth in ACT’s transport emissions has important consequences for ongoing greenhouse gas reductions in the future. Rising transport emissions are the result of growth in the number and use of vehicles in the ACT, including a rise in diesel-powered vehicles (see Indicator HS4: Transport).
Diesel-powered passenger vehicles have increased threefold in the ACT, from 4% of total passenger vehicles in 2010 to 12% in 2019.26 Diesel engines are higher in greenhouse gas emissions than equivalent petrol-fuelled cars.27 Studies have also shown that the greenhouse gas emissions from diesel cars, utes and vans in Australia have risen sharply since 2011, effectively cancelling out the cut in pollution from new renewable energy replacing some coal plants.28 The large increase in diesel vehicles is also a concern for air quality given their higher emissions of nitrogen oxides and much higher emissions of particulate matter (see Air section).
Between 2012–13 and 2017–18, the greenhouse gas emissions from diesel fuel nearly doubled from 230 thousand tonnes CO2-e to 395 thousand tonnes, driving up the proportional contribution of diesel to total transport emissions from 23% to 34% over the same period (Figure CC11). These figures suggest that diesel-powered vehicles are contributing disproportionally higher greenhouse gas emissions compared to petrol vehicles.
To achieve cuts in transport emissions, there will need to be a decrease in the number and use of vehicles in the ACT, especially diesel-powered vehicles. There will also need to be a significant increase in the number of electric vehicles, which combined with the use of renewable energy for charging, will further reduce ACT’s greenhouse gas emissions.
Figure CC11: Main sources of transport greenhouse gas emissions (CO2-e) in the ACT by fuel type, 2012–13 to 2017–18.
Projected changes in emission sources
Transport and natural gas will account for a larger portion of the ACT’s carbon footprint as the electricity sector moves towards zero emissions by 2020. Between 2017–18 and 2020, electricity will have declined to 0% of the ACT’s total emissions, while transport will account for 62% (Figure CC12). Stationary gas and waste will also double in contribution to annual emissions. Transport and the phasing out of natural gas will become the main focus for future reductions of greenhouse gas emissions in the ACT.