The environment is forcing us to rethink our food supply. The sooner we start building a local food economy, the better off we will be

For fifty years we have taken for granted a plentiful supply of cheap food, but pressing environmental considerations may force us to rethink this. 

Cheese and butter prices are set to increase significantly because of a shortage of milk powder caused by severe drought in the US and Australia.

As drought and flood brought on by global warming affect other key supply zones of crucial commodities, we can expect to see further shortages.

Biofuels pose another challenge to our food security. In Mexico recently, there were near riots when ordinary people found the cost of their staple tortillas had shot up because the corn they rely on was being bought up for biofuels.

The supposedly 'green' alternative to oil-derived petrol and diesel, biofuels create new competition for crops such as soya, rape and corn - previously grown only for human or animal food.

This is great news for arable farmers, but what about the rest of us?

The diminishing supply of oil is another concern. BP blithely reassures us that the world has enough oil to last for 40 years.

Independent scientists, on the other hand, insist that 'peak oil' - the point where our consumption of oil outstrips the discovery of new reserves - is only four years away.

The actions of fuel protesters in 2005 exposed how vulnerable our supermarkets' highly centralised just-in-time ordering systems are when fuel dries up. 

Currently, our complex, convoluted food chain - nationally and globally - is totally dependent on oil.

If, for example, al-Qaeda was to bomb a major pipeline in the Middle East or Central Asia, then our food production and distribution systems, which are such profligate generators of food miles and CO2 emissions, would be crippled and our shelves could be bare within days.

A few years back, people who argued that food production and supply urgently needed to be re-localised were ridiculed as New Age hippies, harking back to some hessian past.

Now the model of lots of small 'food webs' of local farmers, growers and producers - who focus on supplying their local consumers - is starting to sound more persuasive.

The environmental apocalypse may still be some way off, but the sooner we start building a food economy based on what is local and biologically

sustainable, the better.n

Joanna Blythman is the author

of Bad Food Britain