Does what I eat have an effect on climate change?
Yes. The world’s food system is responsible for about one-quarter of the planet-warming greenhouse gases that humans generate each year. That includes raising and harvesting all the plants, animals and animal products we eat — beef, chicken, fish, milk, lentils, kale, corn and more — as well as processing, packaging and shipping food to markets all over the world. If you eat food, you’re part of this system.
How exactly does food contribute to global warming?
Which foods have the largest impact?
Meat and dairy, particularly from cows, have an outsize impact, with livestock accounting for around 14.5 percent of the world’s greenhouse gases each year. That’s roughly the same amount as the emissions from all the cars, trucks, airplanes and ships combined in the world today.
In general, beef and lamb have the biggest climate footprint per gram of protein, while plant-based foods tend to have the smallest impact. Pork and chicken are somewhere in the middle. A major study published last year in the journal Science calculated the average greenhouse gas emissions associated with different foods.
The average greenhouse gas impact (in kilograms of CO2) of getting 50 grams of protein from: