Nordhaus is dead, the carbon tax lives on: the market versus the climate?

William Nordhaus died on 30 October, aged 85. According to Le Monde, which publishes a column by Jean-Baptiste Fressoz, the carbon tax, his main recommendation, has become "the economists' martingale" against global warming. The columnist adds that, had the American economist not been followed, another economics of the climate could have taken hold as early as the 1980s.

That much we know. The rest of the column, of which we have only the summary, is beyond us: we will therefore not say what Fressoz demonstrates precisely. What follows is our reading, not his.

A martingale is a method that promises to win every time. Set a price, and the market does the rest. The appeal is obvious: nobody has to decide what to produce, for whom, or which plants to shut down. You adjust a line on a bill. The oil wells, the cement works and the factory farms stay where they are. Only the price signal changes, and the owners of fossil capital keep control of the pace.

We know how this plays out in France. A carbon tax means, first and foremost, a higher petrol bill for those with no alternative to the car. Do the steelmaster and the commuter in the outer suburbs pay the same price? Yes. Do they bear it in the same way? Obviously not. "We are all responsible" finds its fiscal tool here: everyone pays, including those who have emitted almost nothing.

This is where the old notion of the metabolic rift proves useful. Marx described a rift opened by capitalism between human societies and the earth, behind the exhaustion of soils as much as of workers. Today's Marxists apply it to the climate: accumulation demands an ever-growing flow of energy and materials, and pushes its costs onto ecosystems and the poorest populations, who have emitted the least. For Marx, according to John Bellamy Foster, restoring this link was to become a "regulating law of social production". Regulating, therefore collectively decided. Not a price that floats.

The carbon tax treats the symptom, the emission, without touching the cause: a system that produces for profit rather than for need. It does not question the ownership of fossil fuels, the subsidies that bathe them, or the investment decisions taken in a handful of boardrooms. It turns a question of power into a question of accounting.

That is no reason to scorn every price on carbon. It is a reason to refuse that it should stand in for policy. Planning the exit from fossil fuels, financing public alternatives, making big emitters pay rather than households: these options existed, if we are to believe the column, before the martingale chased them from the debate. It is fair to ask whom this forgetting has served.

We do not bury an economist with a trial of intent. We can, however, look at what his legacy made thinkable, and what it made unthinkable. Forty years of carbon pricing, and emissions have not fallen as promised. The bill, meanwhile, keeps arriving at the same counter.