While the grow-your-own ethos has gained popularity in the United States in recent years, for many people around the globe, having a garden is not a matter of choice. In many places it’s still your backyard, not the grocery store, that provides the bulk of your food. Globally, 70 percent of the food supply comes from smallholder farms — and if climate change continues unabated, those subsistence growers may be the ones most dramatically affected.