How much does what you eat pollute the environment?

That's the question that people in Britain will be able to answer if plans go through to add such information to the labels of foods in that country:

Last week Tesco announced it would introduce labels on its products, detailing their carbon footprint. The information, it said, would go beyond the mere question of food miles - how far the produce has been transported - to include indirect greenhouse emissions given off during its production and processing.
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In principle, the concept is easy. A so-called "life-cycle analysis" tots up the energy used to extract raw materials and turn them into products. The greater the energy use, the greater the carbon footprint, and the worse for the environment a product is. Tesco says such information would allow consumers to shop according to their environmental conscience. As demand for more damaging products falls, the thinking goes, so will the stocking of that product.

Naturally there are issues that will need to be resolved:

The problems start in deciding exactly what emissions should be counted. Direct carbon use is easy to measure, but indirect emissions are far more difficult. Should supermarkets include the electricity used to refrigerate products in their stores? What about the fuel in the tractors on a farm thousands of miles away? And if you think the answer is obvious, what about the fuel in the cars the farmworkers drive to get to work? "Boundaries are hugely difficult and, of course, the boundaries may not be in this country," says Dr Boardman. Some experts even argue the audited supply chain should extend as far as the ultimate source of energy - the sun.

But I think that this is a very interesting concept.