At first glance, organic farming seems like a clear climate win because it doesn’t use synthetic fertilizers, which require lots of energy, and thus lots of fossil fuels, to produce. (Both synthetic and natural fertilizers also release nitrous oxide, a powerful greenhouse gas, after application.)

But dig a little deeper, and the science gets stickier. Because they don’t use synthetic fertilizers, organic farms usually have lower yields than conventional farms. That means they often need 10 to 30 percent more land to produce the same amount of food, said Michael Clark, a food systems researcher at the University of Oxford.