Which foods have the largest impact?
Meat and dairy, particularly from cows, have an outsize impact, with livestock accounting for around 14.5 per cent 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:
Now, these are only averages. Beef raised in the United States generally produces fewer emissions than beef raised in Brazil or Argentina. Certain cheeses can have a larger greenhouse gas impact than a lamb chop. And some experts think these numbers may actually underestimate the impact of deforestation associated with farming and ranching.
But most studies agree with this general hierarchy: Plant-based foods usually have a lower impact than meat, and beef and lamb tend to be the worst offenders by a considerable margin.
Is there a simple food choice I can make that would reduce my climate footprint?
Consuming less red meat and dairy will typically have the biggest impact for most people in wealthy countries. That doesn’t necessarily mean going vegan. You might just eat less of the foods with the biggest climate footprints, like beef, lamb and cheese. If you’re looking for substitutes, pork, chicken, eggs and mollusks have a smaller footprint. But plant-based foods like beans, pulses, grains and soy tend to be the most climate-friendly options of all.