According to the Environmental Protection Agency, we throw away about 35 million tons of food every year. Even though food waste is organic, in a landfill condition it can degrade and create methane gas, which is a potent greenhouse gas. The simplest way to combat this is to stop the waste. Buy in bulk only if you really need it; while it may be tempting to get a huge jar of artisanal olives, ask yourself if you're really going to eat all of it. Also, use a shopping list at the grocery store; the EPA estimates people who use a list stick to meal plans. Finally, before you head to the store, look inside your fridge and pantry. If you can make a meal, do it.