Ross Garnaut, the federal government's top climate change adviser, handed down his final report this week.
It contains a timebomb for Australia.
Prof Garnaut thinks that over time, the world will move towards a system of individual pollution allowances for all humanity. Each of us will have the right to pollute a certain, fixed amount, regardless of where we live.
While the proposition is arguably fair and logical, it is very big news for Australia.
Why? Because Australia has just about the highest per-capita emissions on the planet, thanks to the large mound of coal upon which this country sits.
So when the world starts talking per-capita pollution allowances, Australia has the most to lose, in terms of greenhouse gas emissions.
The reason the writing on the wall is so small is that the push towards per capita allowances is seen to be long-term.
Prof Garnaut thinks we should get there in 2050 when, with all due respect and taking into account his hearty demeanour, he may not be alive.
But a new generation of Australians certainly will, and they could face the toughest task in the world in cutting their greenhouse gas emissions.
The debate over how the world should do its greenhouse maths throws up some interesting issues about the value of people from different countries, and the nature of citizenship in the globalised world.
Put simply, does an Australian have the right to pollute more than an Indian?
Currently, the base unit in climate talks is each country's total emissions.
So Australia tots up its total emissions, as does China, France and Bangladesh, and they compare the results between them.
By this measure, China's emissions look huge, while Australia's emissions look small.
But doesn't this system penalise countries with large populations, and give an easy ride to countries with small populations?
On the other hand, it could be argued that countries with large populations should be held responsible for having so many people. Australia could be seen to deserve the credit for keeping the birth rate low, and putting less pressure on resources.
The alternative model, which Prof Garnaut wants us to look at, is for each country to tot up its per-capita emissions. By this measure, China's emissions look low, while Australia's look sky-high.
"Australia's per-capita emissions are the highest in the OECD and among the highest in the world," Prof Garnaut's final report says.
"Only five countries in the world rank higher - Bahrain, Bolivia, Brunei, Kuwait and Qatar."
Australia's emissions averaged 28 tonnes of greenhouse gases per person in 2006.
The OECD average is 14. The world average is seven. The US comes in at about 20.
China, as the country with the highest total emissions in the world, is often singled out as the biggest greenhouse offender. But if a Chinese person emits eight tonnes of greenhouse gases a year, and an Australian emits 28 tonnes, who should do the most to cut emissions?
The reason Australia ranks so high on per-capita emissions is coal.
The nation gets more of its energy needs from coal than other developed countries, and less energy from renewable sources, nuclear power, gas and petroleum. Burning coal generates high levels of carbon dioxide.
For Prof Garnaut, a per capita-based global climate pact is ultimately the fairest approach. He also thinks it's the best way to win over developing countries.
"The approach that seems to have the most potential to combine the desired levels of acceptability, perceived fairness and practicality is one based on gradual movement towards entitlements to equal per capita emissions," his report says.
He calls this "modified contraction and convergence ... the idea that over time, the entitlements of countries to emit should increasingly be linked to their population."
Prof Garnaut has modelled an example of how the system might work. World leaders choose a per-capita allocation of three tonnes of emissions per person, for the year 2050.
Under the modelling, Australia would have to cut its per-capita emissions from 26 tonnes when the post-Kyoto era begins in 2013 to three tonnes by 2050.
China must come down from eight to three tonnes.
India can actually increase its per-capita emissions in that period from two to three tonnes.
This model shows the scale of the task Australia could face - and it shows why a per-capita system is in the interests of developing nations.
Australia is in the throes of a vigorous argument about which sectors of the economy and society should do the most to cut greenhouse gas emissions. While this debate rages, its emissions continue to rise, according to data released last week.
Prof Garnaut's comments on the likely shift to a per-capita pollution allowance should be sounding the alarm: that there could be a very large task in front of us.
