This may be a step in the right direction

Posting the CO2 count on food labels in Sweden

http://www.nytimes.com/2009/10/23/world/europe/23degrees.html?partner=rss&emc=rss

but it would be even better if they posted the total impact on greenhouse gases - including methane, for example.

And if carrots are a better choice than tomatoes or cucumbers - grown in hothouses - and barley than rice - the parallel may be encouragement to eat even more rhubarb, that northerly fruit substitute.