The Rudd government keeps stressing the point that Australia’s ETS targets of 5 – 15 % on a per capita basis are higher than the European Union’s aim to make a 20 per cent cut by 2020.

“If the Europeans were to embrace the same per capita obligations that we are about to embrace then you would be seeing European reductions in the vicinity of 30 per cent,” Rudd has said over the past few days.

Here’s a table from the White Paper:

The Australian government estimate of per capita percentage emissions reductions implies that with a 15% reduction in aggregate emissions, Australia will experience a 41% reduction in per capita emissions because of an anticipated rise in population. Why? We don’t have a finite amount of carbon emissions offset by more people do we? Don’t more people add to our emissions?

We asked climate correspondent Ian McHugh:

Australia’s population is expected to grow by 45% between 1990-2020. If Europe adopts a 30% target for 2020, its emissions (according to govt figures again) will be reduced by 34% per capita because population across the EU is relatively stable. This is a clever take by the government, but this is one time when we actually can say that what matters as far as climate is concerned are each country’s aggregate emissions.

It also doesn’t mention that the government has some control over the population lever, and governments of both stripes have never had the guts to actually confront the question of how many people this country can take. Finally, remember that our reduction would be shaving us down from 26tCO2-e/year/person, whereas the comparable number for the EU is about 11. We will still be far bigger per capita emitters. 

Still confused? Say you have a country containing ten people that each emitted 1 unit of carbon in 2000. That means that total emissions for that country for year 2000 are 10 units. Then say that by 2020 you knew you would have fifteen people but you wanted to reduce total emissions relative to 2000 by 5%. That means that you would have 9.5 units of carbon to share out across the population of 15 people in 2020. Then that means you now only have 9.5/15 = 0.633 units available per person, instead of 1.

That equates to a percentage reduction of (1-0.633)/1×100 = 37% per person. So even though the total emissions only dropped by 5%, the number of people increased by 50% and as a result the emissions per person dropped by 37%. If on the other hand your number of people had remained static, the aggregate and per capita emissions reductions would be the same.

The government has done it this way to underscore the contribution Australia is making, and it’s worth noting in those terms, but they have assiduously avoided any mention of per capita absolute emissions, or for that matter any comparison of those figures with the EU. Ours are scandalously high, and untenable in a carbon constrained world.

And just to make it murkier, Tim Colebatch is disputing the numbers in The Age today, saying, “on the Bureau of Statistics’ median estimate, Australia’s population is on track to grow by 48 per cent between 1990 and 2020, not 45 — from 17.1 million back then to 25.3 million. But Europe’s population growth has also accelerated as migrants flood in. Last year it added almost as many people as Australia has in the past decade. Its population is already 6 per cent bigger than in 1990. Eurostat projects 9 per cent growth by 2020, but that now looks conservative.”

Crikey welcomes your dumb questions, and will find someone smart to answer them. Send your suggestions to boss@crikey.com.au with “clarifier” in the subject field.