I’VE got a blog post up at The Guardian having a look at Australia’s current and future arsenal of “carbon bombs” – those massive multi-billion dollar projects to extract and mainly export fossil fuels.

But before you go off and lose yourself in The Guardian’s website (it’s got electric bees and Mark Hamill for goodness sake), I thought it worth dwelling on a load of numbers about CO2 (you’ve all gone already haven’t you?).

In The Guardian piece, I’ve highlighted a new study  published in the journal Biogeosciences (yeh I know, it’s not Return of the Jedi is it, but just hang on in there) by a team of 10 researchers, eight of which are at Australia’s CSIRO.

The study is an attempt to get a better handle on the flow of greenhouse gas emissions across different industry sectors and across borders.

For me, the really interesting bit was when it looked at how much greenhouse gas Australia emits at home from burning fossil fuels compared to the fossil fuels we export for someone else to burn instead. The climate, after all, doesn’t give a monkey’s chuff who or where the fuels are burned.

The numbers in the study come out looking like this. In 1990, Australia emitted 279 Mt of CO2-e from burning fossil fuels in Australian power plants. By 2010, this had gone up to 418 Mt CO2-e.

Now to what we export. Between 1990 and 2011, Australia exported 513 Mt CO2-e a year over that period. But it’s accelerating due to the booming coal export industry. In 2010, the study shows that Australia’s exports of coal and gas would generate 884 MT of CO2-e when it was burned.

To put this number into further context, Australia still has a target to cut emissions from their levels in 2000 by 5% by 2020. According to the Treasury, this gets us down to 530 Mt by 2020. Without the target, we’d be up at something like 679 Mt CO2e.  That’s a saving of 149 Mt CO2-e – a saving scrubbed out five times over by our exports now.

And there’s much more exporting action to come.

In October 2011, I highlighted one of the first international studies to look closely at the trading of emissions between different countries. Carnegie Institute for Science’s Steven Davis, who was also one of the co-authors on this most recent Biogeosciences paper, had found that in 2004 Australia was already responsible for double its “official” carbon footprint thanks to all the coal and gas we were sending to Japan, China and other mainly Asian countries.

One issue which both these studies raise, is at what point in the chain from digging up fossil fuels to burning them, do you decide to impose the tax? As things stand the worldwide convention is that you make the burner of the fuel pay the carbon price to their nation’s government.

So what might happen if countries decided to tax all carbon emissions at the point of extraction – that is, at the gas well or the mine mouth? The result for Australia is obvious. Tax emissions at the point of combustion, and other countries get the cash. Tax at the point of extraction, and Australia recoups far more.

I guess it all comes down to where you think the responsibility for greenhouse gas emissions sits. When it comes to coal, gas and oil for energy, it’s not being pulled out of the ground for us to look at.