The CBC reports on two new studies that examine the effects of organic vs. conventional agriculture, and purchasing food from local vs. non-local vendors. They come to some disappointing conclusions on their impact on your carbon footprint. So while there are lots of good reasons to buy local or eat organic, mitigating climate change isn't necessarily one of them. The good news is that the studies do provide some answers on what does work.

Organic agriculture used 25 to 110 per cent more land than conventional agriculture — not ideal — but 15 per cent less energy. That's largely because yields are lower with organic agriculture, but a lot of energy is needed to make synthetic fertilizers and pesticides.

Carbon footprints are similar in the production of organic and conventional foods. Considerable energy is needed to make chemical fertilizers and pesticides, but organic and conventional food production emit about the same total amount of carbons. That's partly because organic fertilizers tend to cause the release of nitrous oxide, a potent greenhouse gas, offsetting the lower emissions from energy use in organic production, the study found.

Source: Bad news: Eating local, organic won't shrink your carbon footprint, CBC News.