Though there’s no clear evidence that Roundup or Roundup Ready crops are unsafe, proponents of an alternative vision of agriculture see those expensive GM seeds as a costly input to a broken system. Modern agriculture, they say, already relies too heavily on synthetic fertilizers and pesticides. Not only are they unaffordable for a small farmer like Juma; they pollute land, water, and air. Synthetic fertilizers are manufactured using fossil fuels, and they themselves emit potent greenhouse gases when they’re applied to fields.