I do buy organic, not because the food is better, but because it promotes sustainable food production. Conventional farming taxes the land pretty extensively, requiring synthetic pesticides and fertilizers to produce crops. Those synthetic products, apart from any side effects to the planet, require non-renewable resources to be created. Oil specifically. As a result, a significant amount of energy goes into producing the food than is received back out in the crop. From the National Organics Standard Board, here is the definition of organic:
Organic agriculture is an ecological production management system that promotes and enhances biodiversity, biological cycles and soil biological activity. It is based on minimal use of off-farm inputs and on management practices that restore, maintain and enhance ecological harmony.
It would seem, that while organic farmers certainly do still use fertilizers and methods of controlling pests, they have to do it in ways that rely on the most renewable of energy resources, the sun. This only seems like it would benefit the world in the long term, and would further reduce our dependence on foreign oil.
I was also under the impression that there is a significant amount of food that is produced in the United States that is destroyed each year because the supply far outweighs the demand. It seems this is primarily in the rice and grain categories, but if there is motivation to use that farm land in a sustained way for other crops that fall under the organic label, then I want to continue to support that. And there is no better motivation than higher margins from consumers that are willing to spend more money for the same food.
So, even if The Economist tells me I'm wasting my money and harming the earth by purchasing organic foods, I'm going to keep doing it. I enjoyed having my choices challenged, though. It forced me to go look things up and make sure that I wasn't just making myself feel better by some rationalization.