Trends in emissions

2016

Absolute aggregate emissions

Between 1990 and 2015, Australia’s national GHG inventory suggested that emissions decreased 0.1 per cent (Figure ATM10).

Since 2006, Australia’s emissions (including land use, land-use change and forestry—LULUCF) have decreased by an average of 1.1 per cent per year. This compares with an average increase of 0.3 per cent per year from 1990 to 2000.

When LULUCF emissions are excluded from the determination of total emissions, emissions have generally increased. For example, between 2002 and 2007, the average growth rate was 0.9 per cent per year. During the global financial crisis, Australia, like most countries, experienced a lower growth in annual emissions, with emissions increasing by only 0.5 per cent between 2008 and 2009. By comparison, the United States and European Union reduced emissions growth by approximately 1.4 per cent per year during the same period.

Sectoral emissions

The energy sector generates emissions from stationary energy, transport, and fugitive emissions from fuel extraction. The sector continues to be the dominant source of Australia’s GHG emissions, accounting for 76 per cent of net emissions in 2015 (Figure ATM11). Emissions from stationary energy have increased by 44 per cent, or 85 MtCO2-e, since 1990. This increase has been driven by a mix of factors, notably rising population and household incomes, and growth in demand for energy associated with substantial increases in the export of resources.

Solid fuel emissions from stationary energy tend from fluctuate year to year depending on the volume of coal mined and the share of production from underground compared with surface mines. Increases in emissions in this subsector have not grown as fast, because the trend is for more activity from less emissions-intensive surface mines than for the more emissions-intensive underground mines.

Since 1990, emissions from crude oil and natural gas activities have decreased; however, this is in contrast to increasing production activity (particularly natural gas). This inverse relationship is largely attributed to technological improvements, particularly in Australia’s natural gas distribution network.

Fugitive emissions from fuel extraction occur during the production, processing, transport, storage, transmission and distribution of fossil fuels such as coal, crude oil and natural gas. This sector accounted for 7 per cent of Australia’s GHG inventory in 2015. Emissions from this sector have increased by 5 per cent on 1990 levels, driven by an increase in emissions from solid fuel extraction (e.g. coal) of 13 per cent. This was partially offset by a decrease of 13 per cent in emissions from crude oil and natural gas extraction. Despite long-term declines, emissions from this subsector increased by 5 per cent between 2014 and 2015.

The transport sector generates emissions from the direct combustion of fuels in transportation by road, rail, domestic aviation and domestic shipping. The main fuels used for transport are automotive gasoline (i.e. petrol), diesel oil, liquefied petroleum gas and aviation turbine fuel. In 2015, transport accounted for 17 per cent of Australia’s national GHG inventory. Emissions from transport have increased by 51 per cent, or 31 MtCO2-e, since 1990. Transport emissions growth in Australia is relatively steady at around 2 per cent per year, in line with population growth and an increase in the total kilometres travelled by main transport modes such as cars. This growth, however, has been partially offset by steady improvements in the fuel efficiency of cars and trucks.

Emissions from agriculture include methane and nitrous oxide from enteric fermentation in livestock, manure management, rice cultivation, agricultural soils, savanna burning and field burning of agricultural residues. Emissions from agriculture accounted for 15 per cent of Australia’s GHG inventory in 2015. This sector is the dominant source of both methane and nitrous oxide emissions; it also includes CO2 emissions from the application of urea and lime. Non-CO2 emissions are reported under agriculture; however, CO2 emissions and removals from savanna burning are reported under the LULUCF sector. Since 1990, agriculture emissions have fallen by 8 per cent, or 7 MtCO2-e. Initially, this decline was driven by a fall in sheep numbers; however, by the late 1990s, it was balanced by increasing beef cattle numbers (reflecting changing relative returns to each industry). From 2002 to 2010, and then again in 2015, livestock populations declined in response to drought conditions. This, along with reduced production of many key crops in 2015, has also contributed to the reduction in agriculture emissions.

Industrial processes and product use (IPPU) includes emissions from processes used to produce chemical, metal and mineral products, as well as emissions from the consumption of synthetic gases. In 2015, IPPU accounted for 6 per cent of Australia’s national GHG inventory. Since 1990, emissions from this sector have increased by 22 per cent, principally because of emissions growth from the manufacture of chemical products. In recent years, growth in this sector has been partially offset by the closure of Australia’s only soda ash production facility in 2013, and declines in metal production associated with the permanent closure of a Port Kembla blast furnace in New South Wales in 2011 and the Point Henry aluminium smelter in Victoria in 2014.

The waste sector generates emissions from landfills, wastewater treatment, waste incineration and the biological treatment of solid waste. Emissions largely consist of methane, which is generated when organic matter decays under anaerobic conditions. In 2015, waste accounted for 2 per cent of Australia’s national GHG inventory. Because waste degradation is a slow process, estimates of methane generation for 2015 reflect waste disposal for more than 50 years. Waste emissions have fallen by 38 per cent since 1990, mainly because of increases in methane recovery during the past 5 years, resulting from a combination of regulatory pressure and commercial gain through use of the methane as an energy source. It is also notable that, recently, as rates of recycling have increased, paper disposal in particular has declined as a share of total waste disposed. Total waste disposal has also declined in recent years as alternative waste treatment options become more viable, driven by state and territory waste management policies.

The LULUCF sector includes estimates of net anthropogenic emissions for forests and agricultural lands, and changes in land use. The principal subclassifications of the LULUCF sector under the Kyoto Protocol classification system are deforestation, forest management, afforestation and reforestation, grazing land management, and crop land management. The sector accounted for 2 per cent of Australia’s GHG inventory in 2015. Net emissions from LULUCF have decreased by 88 per cent since 1990, predominantly driven by a decline in emissions from deforestation and grazing land management.

Emission levels of the LULUCF sector tend to vary significantly from year to year, reflecting climate variability. Peaks are often associated with extreme events such as bushfires and drought, which lead to major loss of carbon from vegetative and soil sinks. This results in large variations in the GHG emissions profile of the sector from year to year; in some years, this sector is a net source of emissions, whereas, in other years, it is a net sink.

Sectoral emissions profiles

Each of the sectors in Australia’s inventory has a different emissions profile (Figure ATM12).

 

Most of the CO2 emissions in the 2015 inventory occurred in the energy sector, contributing 93.9 per cent.

Most methane and nitrous oxide emissions in the 2015 inventory occurred in the agriculture sector, contributing 59.3 per cent and 72.0 per cent, respectively (see also Box ATM9).

Although 96 per cent of waste emissions consist of methane, this sector represents only 11.4 per cent of methane emissions in the inventory.

Emissions from IPPU are also CO2 rich, despite contributing only 4.7 per cent of total CO2 emissions. This sector is unique in that all synthetic gas emissions in the inventory, which include HFCs, PFCs and SF6, are sourced from IPPU (Figure ATM13).

Analysis of emissions trend drivers

An equation known as the Kaya identity (equation 1), developed by the Japanese energy economist Yoichi Kaya in 1993 and used by the IPCC in the development of future emissions scenarios, supports the previous analysis of the drivers of Australia’s emissions trends. The equation expresses CO2 emissions from fuel combustion and IPPU as the product of 4 factors: population, GDP per person, the energy intensity of the economy, and the emissions intensity of the energy.

where:

P = population

GDP = gross domestic product

Energy = total net energy consumption

CO2 = CO2 emissions from fuel combustion and IPPU

Trends in these factors provide an insight into how Australia’s national circumstances have affected CO2 emissions since 1990. However, it should be noted that each factor is not necessarily independent of each other (e.g. increases in GDP per person may change the energy intensity of the economy), and an increase in a single factor will not automatically result in a corresponding change in CO2 emissions (e.g. an increase in population does not automatically result in an equivalent increase in CO2 emissions).

Between 1990 and 2014, CO2 emissions from fuel combustion and IPPU increased by 41 per cent (Figure ATM14). Underlying growth factors were a 38 per cent increase in population and a 51 per cent increase in GDP per person. Factors contributing to a decline were a 29 per cent decrease in the energy intensity of the economy and a 5 per cent decrease in the emissions intensity of energy consumption. During the period, Australia’s CO2 emissions trended upwards until 2009, before declining to 2014 as the impact of improved energy intensity of the economy and lower emissions intensity of energy more than offset increases in population and GDP per person.

Figure ATM15 attributes annual emissions changes to the 4 underlying factors. The combined impact of increases in population and GDP per person have contributed to increasing emissions in all years. The energy intensity of the economy decreased in 20 of the 23 years at varying rates per year, reflecting energy efficiency improvements and structural change in the economy towards less energy-intensive service sectors. The emissions intensity of energy has fluctuated during the timeseries; a declining trend has been seen since 2005 as the proportion of electricity generation from coal has declined.

This analysis considers a subset of Australia’s total emissions. At the national level, increases in CO2 emissions from fuel combustion and IPPU have been offset by declines in other emissions sources. Figure ATM16 expands the decomposition to include other emissions sources as a fifth driver of total emissions. This analysis does not attempt to break down other emissions into underlying drivers such as energy consumption, population or GDP growth, which have less of an effect on these types of emissions.

Changes in other emissions sources generally have a downwards impact on total emissions, but annual changes are subject to considerable variation.

Keywood MD, Emmerson KM, Hibberd MF (2016). Climate: Trends in emissions. In: Australia state of the environment 2016, Australian Government Department of the Environment and Energy, Canberra, https://soe.environment.gov.au/theme/climate/topic/2016/trends-emissions, DOI 10.4226/94/58b65c70bc372