Through that lens, animal products sit at the top of the list of emitters. For instance: Producing a kilogram of lamb means emitting 39 kilograms of carbon dioxide, 13 times as much as producing a kilogram of potatoes.
But there is no one correct way to measure emissions. Consider this: When you quantify emissions released on a per-calorie basis, broccoli emits more greenhouse gas than pork or chicken, according to data presented by The Washington Post.
Viewed through this lens, animal agriculture is still the biggest contributor to greenhouse gas emissions. But some types of meat actually started to look like less serious climate offenders. When factoring emissions by calorie of food produced rather than weight, emissions from eggs, cheese, and farmed salmon fall relative to other foods. Meanwhile, emissions from tofu, broccoli, tomatoes, and 2% milk production all climb relative to their by-weight emissions.
