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The scientists behind reckon they've found an easier way for politicians first to conceptualise and then to stop human-induced climate change.

On both fronts, they say, it's better than the time-honoured, of stabilising greenhouse gas concentrations "at a level that would prevent dangerous anthropogenic interference with the climate system".

Logic is with them on the first part of the argument; but I'm struggling with the second.

Let me backtrack a bit. This week's study by a group led from Oxford University by Myles Allen and Dave Frame - two of the young Turks of UK climate modelling, though they'll probably hate me using that appellation - concludes that what matters isn't the level at which carbon dioxide emissions are stabilised, but the total amount of the gas that humanity produces.

Their computer modelling suggests that on the timescales we're talking about - tens of years, possibly a hundred - it doesn't matter whether the emissions come in one huge splurge and then crash to zero within a few years, or whether they're much flatter over time.

All that matters is that total emissions should remain below about one trillion tonnes of carbon (3.7 trillion tonnes of carbon dioxide).

That amount is likely to produce an average global warming of 2C - a threshold that more than half the world's governments do not want to cross, because they believe it would usher in dangerous climate change.

So we can either have a lot of jam today and none tomorrow, or spread it more thinly around the decades. If our generation is greedy, our children's will bear the cost; if the West hogs all the "emissions space", developing countries will be left with none.

"It treats emissions of carbon dioxide as though they're a finite resource," Dave Frame explained when he chatted with reporters on Monday, "and economists are quite comfortable with that."

If something resembling a global carbon market came into existence based on this approach, the logical conclusion is that the price of emitting carbon would increase first slowly and then with a huge rush as the trillion tonne limit approached.

Can the idea enter international negotiations and become a keystone of some future climate treaty - if not the one that's supposed to be agreed in Copenhagen at the end of this year then the one that comes after Copenhagen?

Intuitively it is simple, but I would suggest there are three very big political problems. One is that as with everything connected with climate science, there are uncertainties in the sums; the model concludes that a trillion tonnes could produce as little as 1.3C or as much as 3.9C - almost double the widely accepted target.

Myles Allen says this is easier to deal with than under the stabilisation approach, because as you head towards a trillion tonnes (about 40 years away, at current rates of burning) you see physical effects on the climate which reduce the uncertainties, so telling society whether it can "safely" go beyond a trillion tonnes or whether it must pull up short.

Even so, formulating an agreement that includes this uncertainty still looks difficult, because the target would constantly be shifting.

The second problem is that the atmosphere's capacity to accept carbon emissions isn't really a finite resource like oil or gold; you can always go beyond it if you need to, just as a government that sets a limit on borrowing can always simply break the limit when a banking crisis comes along.

If countries went for more jam today, they might be looking at cutting emissions by 10% per year as the trillion tonnes figure loomed - is it not certain that at that stage, the pot of jam would find itself magically expanding?

And thirdly, the trillion tonnes approach implies that governments accept that at some stage - within decades - humanity's carbon emissions will fall to zero, or something very close to it.

For many, that will be a stark and scary thought; the idea of a "safe", stable level of emissions seems much easier to deal with emotionally.

(A related issue is that the concept only applies to carbon dioxide because of its complex relationship with the atmosphere, oceans and biosphere; so a future treaty might have to mandate stabilisation goals for them and a total cap on CO2, adding another level of complexity).

Framing the issue in these terms may make more scientific sense and may make it easier to conceptualise.

But ultimately, cutting carbon is still a matter of political will.

If governments are serious about accepting the risks of escalating emissions - as their endorsement of the reports implies - and about their commitment to preventing dangerous climate change - as their ratification of the UN climate treaty indicates - they will find ways to keep emissions within "safe" bounds.

If they are not serious, it doesn't matter how you slice up the problem - it won't be solved.

That is surely the simplest and most accurate of all conceptualisations.

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