Beef production in the US is damaging to the environment, a new study has found.

The study states that US livestock production causes about one-fifth of global greenhouse gas emissions and its the key land user and source of water pollution by nutrient overabundance. However, it’s beef production which it finds issue with. It says that beef production, in the US, requires 28 times more land and 11 times more water than other livestock production such as dairy, poultry and pork.

Reported in the Proceedings of the National Academy of Sciences, the study says that livestock production impacts air and water quality, ocean health, and greenhouse gas (GHG) emissions on regional to global scales and is the largest use of land globally.

Quantifying the environmental impacts of the various livestock categories, mostly arising from feed production, is a grand challenge of sustainability science, it says and quantifies land, irrigation water and reactive nitrogen (N) impacts due to feed production.

Its calculations show that the environmental costs per consumed calorie of dairy, poultry, pork and eggs are mutually comparable, but strikingly lower than the impacts of beef. Beef production requires 28, 11, 5 and 6 times more land, irrigation water, GHG and N respectively than the average of the other livestock categories.

It says that US beef production also competes with biodiversity and promotes species extinction. The study only looks at beef production in the US, and doesn’t compare it to say European beef production.

The authors say they are the first to quantify the scale of the environmental impact beef has over other meat production systems.