I have often spoken of the superiority of heuristically diverse groups of problem solvers with specialized knowledge. It is also true that such groups are improved by diversity of specialty, what is sometimes referred to as cross-disciplinary teams. The lone expert or thinker can make some crushingly stupid assertions.

How far your food travels matters a lot less than what kind of food it is, or how it was produced. According to a recent study out of Carnegie Mellon University, the distance traveled by the average American's dinner rose about 25 percent from 1997 to 2004, due to increasing global trade. But carbon emissions from food transport saw only a 5 percent bump, thanks to the efficiencies of vast cargo container ships.

A tomato raised in a heated greenhouse next door can be more carbon-intensive than one shipped halfway across the globe. And cows spew a lot more greenhouse gas than hens, or kumquats, so eating just a bit less beef can do more carbon-wise than going completely local. It's complicated.

But one thing is clear enough: the farmers in Mexico, China, and Brazil, who produce a lot of the imported food Americans eat, are poorer than the farmers here in Iowa. A lot poorer. The corollary of "eat local" is "don't eat Mexican," so to speak. But the way poor people get less poor is to do business with people who have a lot of money, like us. If the local stuff is mouthwatering, you might as well pony up. But if your salad is made with Mexican lettuce, savor your righteousness.

Tyler calls this wisdom, which makes me doubt them both and discount their views even in their areas of specialization. This is very sloppy thinking and is based on sparse and mistaken information. It doesn't speak well for them.

First, nobody has any idea what the carbon emissions from food production or transportation are. The published numbers have been massaged extensively besides failing to include all relevant factors. It's merely a narrative based on nothing but beliefs.

Second, the GHGs cattle are accused of producing happen whether there are cows or not. It's just normal bacterial decomposition of biomass. Pile the forage on the ground, or just leave it lay where it grows and dies, and the result is the same. It's the same bacteria. Eating less beef will do absolutely nothing about those GHGs.

Worse, though not included in the above retarded analysis, some ill informed pundits claim that one way to reduce such emissions from cattle (and other ruminants such as sheep and goats) is to feed them grain rather than grass since it is easier to digest, bypassing their eponymous rumens. But just a tiny bit of knowledge and thought reveals that GHGs from growing grain are larger and the leaves and stalks of grain plants still decompose bacterially. There is a net increase of emissions but it is off the books in this sort of useless analysis.

Third, The corollary of "eat local" is not "don't eat Mexican". Food trade goes both ways, or better yet, all ways. Food, once grown, will be shipped somewhere. The end result is always the same no matter how you finagle the local issue since surpluses and deficits will be resolved. If winter vegetables are not shipped to folks who prefer local produce they will be shipped somewhere else. Many nations are net food importers. They can't feed themselves. Food will be shuffled about and shipped hither and yon until everyone is satisfied or broke.

The local/global food issue is nonsensical from a carbon or trade perspective. They are irrelevant at best, but so poorly documented and understood that nothing sensible can be said about them. It's all just attitude and ignorance. Sensible reasons to eat local are that it pleases you to have food produced nearby and you wish to patronize growers. Sensible reasons to eat global are that you can get things that are otherwise unavailable. We have no hope of becoming banana independent. (or oil independent for that matter).