3This study measures the current amount of greenhouse gas (GHG) emissions from food production in the United Kingdom and examines the variable effects of omnivorous, vegetarian, and vegan diets on GHG emissions. The study finds that the food supply in the U.K. accounts for 22%-27% of all GHG emissions. Emissions could be reduced by 22%-26% if U.K. citizens switched from omnivorous to plant-based diets. The authors contextualize this impact by stating that if U.K. citizens switched to vegetarian and vegan diets, then GHG savings would be equivalent to taking half of the cars in the U.K. off the road.

Article Abstract:

“The greenhouse gas (GHG) emissions embodied in 61 different categories of food are used, with information on the diet of different groups of the population (omnivorous, vegetarian and vegan), to calculate the embodied GHG emissions in different dietary scenarios. We calculate that the embodied GHG content of the current U.K. food supply is 7.4 kg CO2e person−1 day−1, or 2.7 t CO2e person−1 y−1. This gives total food-related GHG emissions of 167 Mt CO2e (1 Mt=106 metric tonnes; CO2e being the mass of CO2 that would have the same global warming potential, when measured over 100 years, as a given mixture of greenhouse gases) for the entire U.K. population in 2009. This is 27% of total direct GHG emissions in the U.K., or 19% of total GHG emissions from the U.K., including those embodied in goods produced abroad.”

“We calculate that potential GHG savings of 22% and 26% can be made by changing from the current U.K.-average diet to a vegetarian or vegan diet, respectively. Taking the average GHG saving from six vegetarian or vegan dietary scenarios compared with the current U.K.-average diet gives a potential national GHG saving of 40 Mt CO2e y−1. This is equivalent to a 50% reduction in current exhaust pipe emissions from the entire U.K. passenger car fleet. Hence realistic choices about diet can make substantial differences to embodied GHG emissions.”

An article about the study can be found here