Raising beef for the American dinner table is more damaging to the environment than producing pork, poultry, eggs or dairy, according to a new study, AP reported.
Compared with the other animal proteins, beef produced five times more heat-trapping gases per calorie, and put out six times as much water-polluting nitrogen, used 11 times more water for irrigation and 28 times the land, according to the study, published yesterday in the journal Proceedings of the National Academy of Sciences.
Cows were not efficient at conversion of feed to protein for human consumption, according to lead author Gidon Eshel, an environmental physics professor at Bard College in New York.
Eshel used US government figures for air and water emissions calculations and the amount of water and land used in the lifetime production of beef, pork, poultry, dairy and eggs.
While there had been other studies that had looked at the issue, this was one of the most comprehensive pieces of research quantifying and comparing the US environmental costs of different meats and other animal protein.
According to the beef industry, the study was "a gross oversimplification of the complex systems that make up the beef value chain."
The Associated Press quoted Eshel to say the average American who switched from beef to pork would cut the equivalent of 540 kilograms of carbon dioxide a year, which was about nine days' worth of the US' per capita greenhouse gas emissions or the emissions from 230 litres of gas, according to the US Environmental Protection Agency, CBC News reported.
However, what one chose to eat instead of beef did not matter so much, since they all had a similar impact, according to the report, co-authored by researchers at Yale University in New Haven, Connecticut, and the Wiezmann Institute of Science in Israel.
Eshel said he hoped the study would help people recognise that their dietary choices could make a significant difference.
While earlier studies considered the environmental impact of certain farm products, Eshel and his colleagues had pooled together data on the five top sources of protein eaten in the US and analysed them all the same way for four different environmental impacts.
The data they had used was available publicly from agencies such as the US Department of Agriculture, the US Department of Energy, and the US Geological Survey.