Charting Transport

[updated in April 2011]

Are greenhouse gas emissions from transport still on the rise in Australia? Are vehicle fuel efficiency improvements making a difference?

This post takes a look at available emissions data.

Australian Transport Emissions

The Department of Climate Change’s National Greenhouse Gas Inventory reports Australia’s emissions in great detail, and 1990 to 2009 data was available at the time of updating this post (there is usually more than a year’s lag before this data is released).

The Department of Climate Change have recently began publishing quarterly reports that includes more recent transport figures. These more recent figures are rounded to the nearest Mt (1 Mt = Mega tonne = 1 million tonnes = 1000 Gg), and I have included them on the chart below. The latest quarterly report estimated calendar 2009 transport emission at 84 Mt and 2010 emissions at 85 Mt, an increase of “1.0%”. The 2009 figure of 84 Mt is lower than the inventory estimate of 86 Mt, hence the following chart shows a slight decline, contrary to the quarterly report growth estimate of 1.0%.

So overall, Australia’s transport emissions show a reasonably steady growth until around 2008, and then perhaps a slight decline in 2009 (probably due to the GFC), before a return to growth in 2010.

In 2010 transport represented 16% of total Australian emissions.

The green coloured area represents road transport, which contributes the vast majority of transport emissions (84% in 2009).

Note that the above chart does not include electric rail emissions (see below), indirect emissions, or emissions from international shipping and aviation. They are included in the following chart lifted from an 2008 ATRF paper by BITRE’s David Cosgrove shows this adds a lot on top (and the future projections are frightfully unsustainable). International transport emissions seem to sneak under the radar in the figures.

Per capita transport emissions

The following chart shows Australian transport emissions per capita have been fairly flat, but with a step down in 2009:

(note: I have used the most recent estimates for 2009 and 2010 emissions in this chart, which are rounded to the nearest Mt)

An aside on electric rail emissions

Electric rail emissions are included under stationary energy, rather than “transport” in the main inventory. However, the inventory of “scope 2″ emissions from electricity suggests that around 2,200 Gg comes from the “Transport and Storage” economic sector (not broken down further unfortunately). Melbourne train and tram electricity emissions have been estimated at 505  Gg for 2007 (ref page 8), and four Australian cities have electric railways, so probably a good chunk of this 2,200 Mt is from electric rail (that said, the inventory estimates Victorian Transport and Storage Electricity emissions in 2007 at 466 Gg). Apelbaum 2006 estimated that Australia electric rail emissions in 2004/05 were 2,082 Gg (ref page 68), which is very similar to the inventory figures.

Sectoral growth trends

Transport is now Australia’s second largest sector,and transport has had the third highest rate of emissions growth (very close to second placed industrial processes).

Within the transport sector, civil aviation has had the strongest growth since 1990 (but note that a lot of this relates to the bounce-back from significant disruptions to domestic aviation in 1990). In recent times rail and domestic shipping emissions have grown while road transport has shown a slight decline in 2009.

And within road transport, freight vehicles have shown the highest growth (the 2009 inventory estimates have been revised upwards significantly from the 2008 estimates). Car emissions have been in decline since 2004.

So is the growth in rail emissions offset by a larger decline in truck emissions? Unfortunately not..

(note: X axis not at zero, and railway emissions include some passenger trains – including Adelaide suburban, long distance, and inter-urban services. Apelbaum 2006 estimated these at 202 Gg in 2004/05 – about 10%).

Transport Emissions by state

The national inventory data allows us to see what is happening at a state level. As my interest is primarily in passenger transport here is a chart for road emissions:

The trends show strongest growth in Queensland and Western Australia, little growth in South Australia, and a recent decline in Victoria (note: the 2008 inventory showed a recent decline in WA, and less recent less decline in Vic, but these have been revised). It’s hard to see the trends on these charts for Tasmania and the territories due to the scale (sorry). And these growth rates will of course depend on various factors, such as economic development and population growth.

The following charts attempt to remove population growth by showing emissions per capita figures for each state (unfortunately the climate doesn’t take into account per capita (or per-GDP) emissions).

These values will depend very much on the state’s characteristics and I won’t even try to speculate the reasons for the differences. However I will note that the figures for NT and WA are much higher than they were in the 2008 inventory figures.

In recent years most states show a decline in road transport emissions (except WA and NT). But I need to drill down further.

Car emissions reductions – mode shift or fuel efficiency?

The following chart shows car emissions per capita (which essentially removes freight from the road transport figures).

Again, all states (except WA and NT) show a decline in recent years, with stronger reductions in the states with cities showing more mode shift to public transport (refer to earlier post on BITRE data).

Is the drop in road transport emissions related to behaviour change and/or fuel/emissions efficiency?

The following chart shows that the average emissions per km of Australia cars has been trending downwards (I’ve used BITRE 2011 Yearbook data on car kms travelled hence a little noise):

We’ve seen more significant declines in car emissions per capita since around 2004. So what if cars had made no improvement in emissions intensity since 2004? The following chart estimates what car emissions per capita would have been in that case:

Car emissions per capita  have dropped from 2.20 to 1.89 tonnes between 2004 and 2009. It would appear that emissions efficiency improvements since 2004 can explain 0.12 tonnes of this difference – around 40% of the overall decline. This would suggest that travel behaviour change has contributed around 60% of the reduction in car emissions since 2004.

What about transport emissions in cities?

As part of the Victorian Transport Plan, the Victorian Department of Transport commissioned the Nous Group to do a wedges exercise on Victorian transport emissions. This report included estimates of Melbourne’s 2007 transport emissions (12,270 Mt). In addition, Apelbaums’s Queensland Transport Facts 2006 was for a brief time on the internet and I was lucky enough to grab a copy. From that report, estimates of Brisbane’s 2003-04 transport emissions can be derived (7,312 Mt).

The breakdowns are remarkably similar:

What does this look like per capita? I’ve also added London and Auckland figures (though I am not aware of the make up of the Auckland data) to create the following chart:

Obviously these cities’ transport systems and energy sources are very different, but it shows what is possible even for a large city like London. Transport emissions will closely follow transport energy use per capita, which has been the focus of a lot of research, particularly by Prof Peter Newman (eg his Garnaut Review submission).

For 1995 measures of passenger transport emissions per capita for other cities, see this wikipedia chart created using UITP Millenium Cities Database for 1995. Note: these figures only include passenger transport and hence are different to the above.

Also, here is some data for US cities from the Brookings Institute, but it excludes industry and non-highway transportation so is not comparable to the above chart.

Other transport-related emissions data post 2007

At the time of writing, detailed transport emissions data from the Department of Climate Change finished at 2009. While we saw some data on total Australian transport emission above, there is also some data available from the Climate Group‘s Greenhouse Indicator program launched in 2007, that tracks energy related emissions weekly.

For transport, their petroleum figures give some indication of emissions, although only around 68% of Australia’s petroleum emission come from transport (according to Department of Climate Change AIEGS data). The petroleum figures are based on monthly fuel sales data, converted to weekly figures (see their methodology).

You need to be very careful about equating these trends to transport, as around 32% of petroleum is used in industrial activities will likely be linked to economic activity and possibly different growth in different sectors. That said, GSP in all Australian states grew between June 2007 and June 2009, so despite the economic growth there was a decline in petroleum emissions. However in early 2011 it looks like petroleum emissions are growing slowly in Victoria, New South Wales and South Australia (and are very static in Queensland).

Where are transport emissions headed?

The most recent data suggests that Australian transport emissions are presently on the rise.

The 2010 Department of Climate Change projections suggest transport emissions will continue to rise, as shown in the following chart lifted from their website:

Most of the forecast growth is expected to come from freight vehicles (trucks and light commercials). Curiously they forecast quite small increases in car emissions.  This is based on forecast significant improvements in emissions intensity but also a return to growth in total car kms travelled (including car kms per capita).

Here is a chart of forecast of car emissions intensity, derived from their forecast data on vehicle kms and emissions:

Perhaps more optimistic is the assumption around future oil prices:

At the time of writing the oil price was $113/barrel (in April 2011 US dollars). Even with an inflation adjustment, this is certainly pushing the high end of their sensitivity testing. This prediction of oil prices doesn’t seem to take into account peak oil, or even much of an oil crunch (where supply cannot keep up with demand).

This entry was posted on Sunday, June 6th, 2010 at 9:30 pm and is filed under Australian Cities, Greenhouse Gas Emissions, Melbourne, Mode shift. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.