Wholesale change is needed to wean people off high-impact consumerism, says Tim Lang

The hostile £28bn BHP Billiton bid for Saskatchewan's Potash Corp is another sign 'business-as-usual' isn't returning after the 2006-08 commodity spike.

When prices fell, optimists welcomed long-term normality resuming. Efficiencies, technologies and globalisation would continue that historical trend, they said.

In fact, the picture is messy, if not murky. The plausibility of business-as-usual as a basis for policy is a bit threadbare. GM crops' global expansion isn't delivering so far, probably because GM development mostly chases profits rather than meeting needs. Commodity prices are rising globally. National Statistics this month described food as a key inflationary driver for UK consumers.

Politicians are in a double bind. On the one hand, for 30 years governments have celebrated private sector virtues, in food especially. But the problems ahead aren't conventional. No food system since the time of the dinosaurs has had to address rapid climate change. None has faced weaning itself off oil, global soil erosion or billions of mouths wanting to eat like the West. This bigger picture requires political leadership.

Skills are central to this new policy territory, so watch out for Lord Taylor of Holbeach's Agricultural Review, now on ministers' desks and out shortly. It's informing thinking in the run up to the chief scientist's two-year Foresight Review in the autumn.

Lord Taylor's few pronouncements emphasise private sector investment, applied research, reliance on consultants rather than having a national advisory service, and ensuring the right skills are available and taught. This mix intrigues me. I detect two approaches to skills. One is top-down and commercial, the kind of approach championed by the Skills Councils (not chopped yet). The other is a 'citizens' approach', trying to build new skills to wean people off high-impact consumerism. One centres on factories and choice editing. The other on lifespace and redefining need.

This policy tension matters. If food companies are more in the driving seat, as the government says they must be, they'll be responsible for meeting the environmental, health and societal challenges. I'm not sure even mighty retailers can sort out climate change, let alone the other dynamics.

New frameworks are needed to adjust markets. It requires wholesale change. Not just buying up potash.

Tim Lang is professor of food policy at City University.