Beef production is much worse for the environment than producing other meats such as pork or chicken, according to two new studies.

Scientists compared land use, water use, and the release of gases when producing beef to the production of other meats. Their study, published online in the journal Proceedings of the National Academy of Sciences, found that beef production in the United States requires 28 times more land and 11 times more irrigation water than other meats. They also determined that beef production pumps at least five times as much planet-warming gasses into our atmosphere.

Cut Back On The Beef

Around the world, there has been a huge increase in planet-warming gases from livestock in the last 50 years. Developing nations that have adopted the U.S. model of meat consumption have helped increase the amount of gases 51 percent from 1961 to 2010, according to another study published in the journal Climate Change.

"For people, the obvious answer is: whenever possible, replace beef with something else," said Gidon Eshel, a geophysicist at Bard College and lead author of the study in Proceedings of the National Academy of Sciences. "If you really need it to be from animal sources, that's still OK. You can still have bacon and eggs and whatever you want. As long as it's not beef, you have always made a significant step forward, because beef is so much more intensive than the rest."

The beef industry, not surprisingly, disputes the results of the studies.

The PNAS study oversimplifies the complex systems that produce beef, according to Kim Stackhouse-Lawson of the National Cattlemen's Beef Association. "The fact is the U.S. beef industry produces beef with lower greenhouse gas emissions than any other country," she said.

Beef Emissions Lead The Way

It's true that harmful gas emissions from developed countries such as the United States have been falling since 1970. But developing countries more than doubled their emissions, mainly due to increased beef consumption.

Beef cattle produced more than half the emissions, followed by dairy cattle (17 percent), sheep (9 percent), buffalo (7 percent), pigs (5 percent) and goats (4 percent), according to the Climate Change study. The largest increases came in Congo, the Central African Republic and Oman, the study found.

Carnegie Institution ecologist Ken Caldeira co-authored the study, which estimated production of methane and nitrous oxide gases in 237 countries over the past 50 years.

"More and more of the developing world is adopting the bad habits of the developed world," Caldeira said.

More Factors To Consider

The other study, from the Proceedings of the National Academy of Sciences, focused on the U.S. industrialized food chain. It considered more factors, including the effects of grazing, raising feed crops and the use of irrigation water.

Still, the study could not pin down every factor that goes into producing meat. There are wide ranges in how much and what cattle eat, depending on geography and the practices of the cattle farmer.

The study should guide not just consumer choice but also government policies, such as grazing fees on public land, Eshel said.

Like many environmental questions, this one comes down to a "tragedy of the commons," according to Eshel. If a resource is free and available, people will tend to use it up until it is gone.