You see, people often tell me that they've given up eating red meat out of concern for animals, the environment, or their health (or all three). Of course all efforts to make the world a kinder and less polluted place should be applauded. But here's the thing: cutting out red meat while still eating chicken doesn't address the whole problem.

Here's why: Both choices -- beef and chicken -- badly damage the environment, so choosing one or the other is sort of like the difference between driving a huge SUV and a Hummer. That's also why I'm a little baffled when some environmental organizations say that cutting out beef is advisable, but eating other meats is "relatively" ok. It's really not.

On the issue of global warming, all animal agriculture is a nightmare, relative to producing grains and beans. In a 400 page report from the United Nation's Food and Agricultural Organization, Livestock's Long Shadow, scientists conclude that the business of raising animals for food is responsible for about 18 percent of all warming -- in fact meat causes about 40 percent more warming than all cars, trucks, and planes combined.

That is in part because turning animals into meat requires many stages of (energy intensive and polluting) production (i.e., transporting feed, animals, and meat; running feed mills, factory farms, and slaughterhouses; refrigerating carcasses during transport and in grocery stores -- chickens are at least as energy consumptive as cattle for all these stages), compared to plant foods.

Environmental Defense calculated that if every American skipped one meal of chicken per week and substituted vegetarian foods instead, the carbon dioxide savings would be the same as taking more than half a million cars off of U.S. roads. Imagine if we dropped all meat from our diets altogether.

And it's not just global warming, of course: In a story about chicken waste pollution, the New York Times reported in November that "[a]lthough the dairy and hog industry in states near the bay produce more pounds of manure, poultry waste has more than twice the concentration of pollutants per pound." I assume that's in part because poultry are given a lot more drugs than pigs and cattle -- because they're kept in even worse conditions and thus require more drugs.

When you have the attorney general of a state like Oklahoma battling poultry producers over the industry "wreak[ing] havoc in the 1-million-acre Illinois River watershed, turning it into a murky, sludgy mess," it seems pretty clear (to me) that environmentalists might want to think again about putting that product into even a "relatively" favorable category.