The biggest lever to cut food emissions is to stop producing more food than we need. The United Nations estimates that the annual carbon footprint of global food waste is 4.4 gigatons of CO2 Americans, specifically, waste about 25 percent of the food we buy. According to Project Drawdown, adopting a vegetarian diet can also cut emissions, by about 63 percent, while going vegan can reduce them by as much as 70 percent. Agriculture is a major source of greenhouse gas emissions, and meat and dairy production are the big contributors. Even cutting back on animal products can make a difference.