Cancun talks puts onus on food companies to sort sustainability problem, says Tim Lang

The Cancun climate change talks last weekend both surprised and disappointed me. Surprised because they looked set to repeat the 2009 Copenhagen failure, only to deliver a last-minute compromise agreement on emissions cuts.

The disappointment was the lack of ambition. Nothing is binding. All is aspirational. A Green Fund is created to help developing nations. An Adaptation Committee is formed. But there are no targets or mechanisms. Who's going to do what? By when? How? With whom?

Where now? Firstly, the problem won't go away. And food is a core challenge, as it accounts for 18% to 20% of emissions, and 30% of all European consumer impact.

Secondly, Cancun renews pressure on food companies. If governments won't get their act together and create a level playing field, food companies are unwittingly hung out to dry. On some products, such as meat and dairy, it's farming that must change. But if retailers sell the stuff, they're liable.

That's driving retailers, working with dairy suppliers, to de-carbonise what they can. But the entire western food system is unsustainable. To eat like the British we need two to three planets. It's not just a matter of climate change but water, land use and oil dependency. Companies that have profited from and shaped this system are in the moral dock.

Thirdly, relying on competition, corporate responsibility or single niche products doesn't pass the policy laugh test. Systems-change requires co-ordination and joint action, before competition kicks in and has a chance to be effective. Although 2010 saw UK and international company initiatives, organisational fragmentation is part of the problem.

The food system has lots of clubs and associations, but lacks systems-wide mechanisms and whole food chain oversight. That's where government ought to help. The last government was timid but belatedly realised the case for new frameworks. So far, the coalition has been focused on cuts, deferring the big changes needed. And the EU has been largely silent.

A thorny issue is changing consumer behaviour. The debate is whether culture shift happens through choice-editing upstream, or by enticement ('buy less meat and dairy, get fruit-and-veg free' offers?), or by mass action, or at all.

Food politics will be interesting in 2011. Happy New Year!

Tim Lang is professor of food policy at City University.