Here's the plan. Everybody gets the same allowance for how much carbon dioxide they can emit each year, and every time they buy a product that involves carbon dioxide emissions filling their car, paying utility bills, buying an airline ticket carbon points are deducted from their credit or debit cards. Like Air Miles, only in reverse.
If you ride a bike everywhere, insulate your home and don't travel much, you can sell your unused points back to the system. If you use up your allowance before the end of the year, you'll have to buy extra points from the system.
This is no lunatic proposal from the eco-radical fringe. It's on the verge of becoming British government policy, and Environment Secretary David Miliband is behind it 100 per cent. In fact, he's hoping to launch a pilot project quite soon, with the goal of moving to a comprehensive national scheme of carbon rationing within five years.
A huge share of total emissions is driven by the decisions of individual consumers. Miliband thinks the least intrusive, most efficient way of shaping those decisions is to set up a system that tracks everybody's use of goods and services producing a lot of greenhouse gases and rewards the thrifty while imposing higher costs on the profligate.
And there is no time to lose: the world's carbon emissions have to stop growing within 10 to 15 years, he says, and Britain must cut its total carbon emissions by 60 per cent in the next 30.
"The science is getting worse faster than the politics is getting better," he told the Guardian newspaper on December 11. "People know the technology exists to get a lot of this done... but there is a huge chasm of mistrust between countries about how to do this."
Developing countries that are only now beginning to emit large amounts of greenhouse gases point to the mountain of past emissions produced by developed countries, the source of most current climate change. They want the rich countries to cut back very deeply deeply enough to leave the developing countries some room to raise their consumption without dooming us all to runaway climate change.
That's where the long-range target of 60 per cent emission cuts for Britain comes from. Britain only produces 2 per cent of global greenhouse gas emissions, so a 60 per cent cut in Britain alone is still only a drop in the bucket, but the aim is to set an example: "See, we can do this without impoverishing ourselves, so other developed countries can, too."
And if they do, then a deal to control the growth of emissions in the developing countries is within reach.
So there will be individual carbon credit accounts for all. And every year or so, as the average carbon efficiency of transport or food production or power generation improves a little bit, the size of the free personal carbon allowance is reduced a little bit. It is, I suspect, the shape of things to come.