Think about climate change long enough and you soon realize that it's more than our lightbulbs that we're going to have to change. Colleagues have already argued on these pages this week, as delegates gather in Bali to hammer out a global accord to avert this catastrophe, that a much more fundamental overhaul will be required, a war on carbon as fierce as the 1940s war on fascism. Madeleine Bunting suggested a return to wartime rationing, in order to curb a hyper-consumerism that is palpably unsustainable.

One could go further, arguing that it is not just excessive consumerism but capitalism's very nature that makes it incompatible with the survival of our planet. For capitalism requires constant economic growth, yet the Earth's resources are finite. Capitalist logic says we must buy, sell and consume more and more each year. Nature's logic says we can't.

Two possible political consequences flow from this, pointing in opposite directions. One scenario would see a reopening of an ideological debate that has remained all but dormant, at least in the west, for nearly two decades. Since the fall of the Berlin wall in 1989, the prevailing assumption has been that capitalism faces no serious rival; no viable alternative system is on offer. Even self-described progressives have been wary of challenging the core tenets of free market economics for fear of looking like outdated leftovers from the socialist past. But now, armed with a plea not only to combat grotesque inequality but to save the human race's only home, progressives could start making the fundamental case against capitalism anew.

The other scenario is that capitalism could fight back, containing not, as the Marxists predicted, the seeds of its own destruction, but perhaps the seeds of its own - and therefore the Earth's - salvation.

That's certainly the impression the capitalists themselves are keen to project. Last week, the Confederation of British Industry put out a report pledging to do "what it takes" to tackle global heating - "warming" is misleadingly gentle - and to play its part in reducing Britain's carbon emissions. Days later chief executives from 150 leading global corporations, Coca-Cola, Shell and British Airways among them, issued a pre-Bali communique calling for a comprehensive, binding UN framework on climate change. Its message to world leaders: rein us in, please!

Now, the grounds for scepticism here are obvious. Most CEOs realized long ago that looking green has become a necessary part of corporate PR. So the CBI makes the right noises even as its signatory companies continue to lobby for more roads and bigger airports. They talk big but promise to cut their current, collective carbon emissions of 370m tonnes by a measly 1m tonnes over the next three years.

Yet some in business are clearly determined to do more than printing the company reports on green-scented, recycled notepaper. Some are realizing that last year's Stern review was right, that business stands to lose more through inaction on climate change than action will cost. In the words of one boardroom chieftain quoted last week: "We mustn't kill our customers."

And the smartest understand that, as in every crisis, there is money to be made. Witness the cash now swilling around the cap-and-trade market in carbon, which grew threefold last year and which the World Bank now estimates is worth at least $30bn. Here's how it works. On January 1 2005, the EU put a cap on how much carbon companies are allowed to emit. If Company A gets an allowance to pump out 1,000 tonnes but only emits half that, it can sell the right to emit the remaining 500 tonnes to Company B, which would otherwise overshoot its allocation. The beauty of the scheme is that it at last puts an economic value on carbon which, until now, cost nothing - even though it literally costs the Earth. This way, runs the theory, companies have a direct financial stake in keeping down their emissions, so that they don't have to pay for credits (or fines) if they breach the cap.

In practice, though, it seems European companies prefer to pay for their sins rather than change their ways. I spoke to James Cameron, co-founder of Climate Change Capital which also takes advantage of the UN's trading scheme far beyond Europe. Cameron will approach, say, a cement company in China and offer to invest millions in a new, greener plant. In return, once verified, the UN will hand the cement firm credits for the carbon it has saved, credits that it can then sell back on the international market. The proceeds are split between the Chinese and Cameron's firm - and everyone's happy.

Except, isn't this robbing Peter to pay Paul, reducing carbon in Beijing only to keep on producing it in Birmingham? No, says Cameron. Reducing carbon in China is more efficient, costing much less than an equivalent reduction in Europe. Anyway, he says, don't be precious about it: his company is taking CO2 out of the atmosphere that would otherwise be in it. The firm's current projects aim to eliminate 70m tonnes of greenhouse gases, equivalent to the entire CO2 output of Denmark.

Getting developing nations to cut back on carbon while we keep belching it out may seem like green colonialism, but Cameron believes the climate crisis allows for no such pieties: we just have to cut carbon as quickly as possible and reductions in China are the lowest-hanging fruit. Besides, European polluters will eventually have to make their own CO2 reductions, since buying allowances costs money. (Not that it's having that effect yet: European emissions have actually risen by 0.8% since the trading scheme started.)

Perhaps capitalism's greatest contribution will come from the thing it does best: innovation. Curiously, many of the consumer advances of recent years have, in green terms, been retreats. Landline phones used to need no mains power; now their "cordless" successors require a base unit permanently plugged in. We used to repair appliances; today their innards come molded together, making repair impossible or more costly than replacement.

Now, though, some savvy designers are rethinking all that from scratch. Not just eliminating waste and packaging, but thinking of consumption in an entirely different way. What if we did not buy a product at all, but merely a service? iTunes provides music, rather than a physical object, and that saves on materials and haulage. Electrolux is testing a new approach to laundry in Sweden, renting, rather than selling, washing machines to customers - thereby giving the company an incentive to prolong each machine's life.

Clare Brass, who has just launched the Seed Foundation for "social environmental enterprise + design", wants to change "the way we make contact with the energy infrastructure". Carbon is invisible and colorless, and so is electricity; we don't see it when we use it. That's why Brass is a big admirer of the Wattson, a neat little gizmo that shows home energy use in pounds and pence, not watts, and which glows redder the more you spend.

On their own, none of these ideas will be enough. And it's clear that some of the headline efforts by global capital creak with contradictions. But some effort by business, alongside government, is surely better than nothing. The alternative is to wait for a political revolution, and a global resolve, that may come too late - or never come at all.