29th Dec 2025 published by: Robert Phillips
Greenhouse gas emissions
Glass half empty or half full?
The expressions ‘glass half full’ and ‘glass half empty’ are used to describe optimists, who rejoice that the glass is still half-full, and pessimists, who lament that the glass is already half empty.
But in dealing with Australia’s greenhouse gas emissions, the terms apply the other way round. In 2005, which was the baseline year for Australia’s 2030 target under the Paris Agreement, emissions were about 630 million tons. Over the last twenty years they have declined to about 430-440 million tons.
So this is a reduction in emissions of around 30%. Yet, in that time, Australia’s population has risen by more than 30%. So, in per capita terms, our emissions have nearly halved from about 30 to 16 tons per person. This means that an optimistic person is pleased that we have virtually cut our per capita emissions in half, a ‘glass half-empty’ person. A pessimist laments that we still have half way to go, a ‘glass half-full’ person.
Given the growth in our economy over that time, it also means more than a halving in emissions per dollar earnt.
I would sound a note of caution at this point: comparing two individual years can be misleading because they may be atypical. (Remember the 1998 fiasco). However, 2005 and 2025 do appear to be fairly consistent in terms of emission rates for years around their time.
The major cause of our emissions reduction is somewhat surprising. Much of it relates to the cumbersome category LULUCF (land use, land use change, forestry). Because of land clearances and timber production in 2005, LULUCF emitted about 70 million tons of greenhouse gases per year. Now, because of restrictions on land clearances, and increases in plantations and native vegetation, LULUCF has become a carbon sink, absorbing about 70 million tons per year.
This means that our total emissions are around 500 million tons, only a 20% reduction in 20 years, but 70 million of that is offset by the LULUCF carbon sink.
The other major area of improvement is in electricity production where emissions have reduced by nearly a quarter, or around 50 million tons. This is because of increasing use of renewable energy, which now accounts for about 40% of our electrical energy production. Some of this is from wind power, some from large scale solar power, and much from the millions of houses that now have rooftop solar. You could say we voted with our rooves.
Agriculture has seen a decline of 8%, in line with declining livestock populations.
On the other hand, transport has seen a 20% rise in emissions, due to increased traffic, and use of more diesel. Given Australia’s size, transport is always likely to be a key component of our energy budget. Emissions from mining operations, including ‘fugitive’ emissions from LNG production, have produced similar increases.
So, in 20 years, we have got half way to reducing emissions on a per capita or per dollar basis. Whether we can go the other half, and achieve zero emissions in the next quarter century, is the big challenge.
REFERENCE
Australian Government. Department of Climate Change, Energy, the Environment and Water, Quarterly update of Australia’s National Greenhouse Gas Inventory: March 2025. (Incorporating preliminary emissions up to June 2025. Australia’s National Greenhouse Accounts.)
