Which Foods Have the Greatest Environmental Impact?

There seems to be an awful lot of confusion about which foods are best—or worst—for our environment. Our World in Data relies on data from the largest meta-analysis of food systems in history.

The study, published in Science, was led by Joseph Poore and Thomas Nemecek to highlight the carbon footprint across different food types across the world and hopefully offer some unbiased facts for us all to learn.

Worldwide, there are about 13.7 billion metric tons of carbon dioxide equivalents (CO2e) emitted through the food supply chain per year.

Across a database extending through 119 countries and 38,000 commercial farms, the study found that, unsurprisingly, beef and other animal products have an outsize effect on emissions.

For example, 1 kilogram of beef results in 60 kilograms of greenhouse gas emissions (GHG), which is nearly 2.5 times the closest food type: lamb and mutton. In contrast, the same weight of apples produce less than 1 kilogram of GHG emissions.

When it comes to plant-based foods, chocolate is among the highest GHG emitters. One kilogram of chocolate produces 19 kilograms of GHGs. On average, emissions from plant-based foods are 10 to 50 times lower than animal-based types. No one disputes that the food supply chain is complex and nuanced as it moves across each stage of the cycle.

Although the steps behind the supply chain for individual foods can vary considerably, each typically has seven stages:

Across all foods, the land use and farm stages of the supply chain account for 80% of GHG emissions.  

On the other end of the spectrum is transportation. This stage of the supply chain makes up 10% of total GHG emissions on average. Contrary to popular belief, according to the report, sourcing food locally may not help GHG emissions in a very significant way, especially in the case of foods with a large carbon footprint.