Australia's natural absorption of CO2 exceeds its man-made emissions

Mark Twain made famous the saying “There are three kinds of lies: lies, damned lies and statistics”.

Contrary to the line repeated constantly by Julia Gillard and Greg Combet, Australia doesn’t have the world’s highest per capita emissions of manmade CO₂. Authoritative figures show that several countries, from large (USA) to small (Qatar, Kuwait), have higher per capita emissions of CO₂ from fossil fuel than Australia.

But here’s the really interesting story: the IPCC’s own numbers suggest that Australia’s annual net absorption of CO₂ over its land and territorial oceans by natural processes exceeds its annual manmade emissions by a factor of 2 – a better performance than any other nation or region. On a net basis, according to the IPCC’s own numbers, Australia doesn’t have any emissions of CO₂ at all - either in absolute or per capita terms.

The IPCC notes that figures from its Fourth Assessment Report, Ch.7, Fig.7.3 (on which I rely for these calculations) carry large uncertainties. For argument’s sake, we’ll accept the IPCC line on global warming (although I don’t buy it) and we’ll use these data.

We begin by figuring¹ annual net absorption of CO₂ over land by natural processes, mainly vegetation and soil: net natural absorption on land is 3.2 billion tonnes/year C-equivalent (122.8 bn.t/yr of absorption minus 119.6 bn.t/ yr of emission). And for oceans, we find that net natural absorption at the sea’s surface is 1.6 bn.t/yr tonnes C-equivalent (92.2 bn.t/yr of absorption minus 90.6 bn.t/yr of emission).

Earth’s surface is 510.1 million square kilometres; the oceans cover 71%, or 362 mn.sq.km; and land covers 29%, or 148 mn.sq.km. The surface area of Australia is 7.7 mn.sq.km, so it covers 5.2% of Earth’s land area; and its maritime ‘exclusive economic zone’ is 8.2 mn.sq.km, which covers 2.3% of Earth’s oceans.

If the IPCC’s figures represent realistic averages over the Earth’s surface, we can apply them to the percentages we’ve derived. Accordingly, Australia’s land mass absorbs 5.2% of the 3.2 bn.t/yr of CO₂ absorbed globally by land, or 0.166 bn.t/yr C-equivalent; and Australia’s oceans absorbs 2.3% of the 1.6 bn.t/yr of CO₂ absorbed globally by oceans, or 0.036 bn.t/yr C-equivalent.

Adding these results, we find that Australia absorbs naturally 0.2 bn.t/yr C-equivalent – twice its man-made emissions from fossil fuel, which totalled 0.1 bn.t/yr C-equivalent in 2010, or 1.1% of global fossil fuel emissions (according to BP Statistical Review of World Energy 2011). We know that Australia is largely semi-arid and is typically less vegetated than other regions; but even if you halve Australia’s rate of land absorption of CO2 from the IPCC global average, the total still exceeds its man-made emissions from fossil fuel.

Doing the same exercise for all other major nations or regions, we find that the truly serious offender in 2010 was China, at 2.3 bn.t/yr C-equivalent. China emitted over 10 times more CO₂ from fossil fuel than it absorbed naturally – worse than any other major nation or region. In 2010, China’s emissions from fossil fuel were 10% greater than in 2009. It produced 23 times more CO₂ from fossil fuel than Australia did! In the space of a single year, China’s fossil fuel emissions grew by an amount more than twice the amount of Australia’s emissions from fossil sources.

It should be obvious to even the most partisan government adviser that a ‘carbon’ tax in Australia won’t have the slightest effect on the world’s growth of atmospheric CO₂ without a similar tax in China – a tax that, almost certainly, will never be imposed. So a ‘carbon’ tax in Australia would not only be economically harmful, but utterly pointless as well.

On a per capita basis, the story gets even better. Australians are indeed big per capita emitters of fossil fuel CO₂, at 4.42 tonnes/year C–equivalent (ahead of China at 1.71t/yr per capita). Unmentioned in government propaganda, Australia’s fossil fuel emissions in 2010 were less than half those of Qataris (10.57t/yr), slightly more than half those of Kuwaitis (8.43t/yr), and about 82% of those of Americans (5.38t/yr).

When we ‘net out’ Australia’s per capita emissions with its per capita natural absorption of CO₂, we find this country performs ten times better than any other nation or region as a net per capita absorber of CO₂. Australia absorbs a net 4.50 tonnes/yr C-equivalent per capita of airborne CO₂; the nearest runner-up is the African continent (0.40t/yr), followed by Brazil (0.38t/yr), and then Canada (0.22t/yr). In both absolute and per capita terms, all other major nations and regions are net emitters of CO₂.