Beef production is by far the most environmentally damaging form of livestock production per human calorie consumed according to a new scientific study published. 

The report, which is published in the Proceedings of the National Academy of Sciences, found that every 1,000 calories of beef for human consumption produces five times more greenhouse gas emissions than other livestock categories. 

It also found that beef calories require 28 times more land, 11 times more irrigation water, and six times more fertiliser than the average of other livestock categories considered. 

The study, which is based on American farm practices, compared all aspects of the land, water, greenhouse gas, and fertiliser impacts involved in the production of five animal based protein foods including dairy, beef, poultry, pork, and eggs.

It did not, however, include sheep production.

One fifth of all global greenhouse gas emissions are the result of livestock-based food production and the study finds that beef is consistently the least resource efficient of five different animal food categories considered. 

The report suggests that if people were to substitute alternative animal-based products for beef it would have a significant beneficial impact on our environment. 

It also compared the environmental impact of beef with three staple crops including potatoes, wheat and rice. 

On that score it found that beef requires 160 times more land than if the same calories were to come from staple crops. Its production also requires 8 times more irrigation water, produces 11 times more greenhouse gas, and requires 19 times more fertiliser than staple crops. 

The scientific study also considered the basic biologically governed capacity of the different animals to convert energy feed into calories for human consumption. 

In this regard it concluded that beef was three to six times and less efficient than other livestock categories. 

The clearest message from the report is that beef is by far the least environmentally efficient animal category for human calorie consumption on all of the measures considered.

The report also suggested that the westernisation of diets in countries like Chinese and Indian, as they become significantly wealthier, could yet have a significant global environmental impact if consumers in those countries start to consume more beef and related products.