Two new studies have found that beef is unhealthy - for planet Earth. Beef production is responsible for the release of gases that contribute to climate change, among other environmental effects.

One study focused on U.S. beef production. It found that producing beef uses 28 times more land and 11 times more water than other meats. The study, published in the journal Proceedings of the National Academy of Sciences, also said that beef production pumps at least five times more planet-warming gases into our atmosphere than chicken or pork.

A study in the journal Climate Change found that developing nations raising cattle have significantly increased the amount of gases they produce - or emit. Planet-warming gases from livestock increased 51 percent from 1961 to 2010.

"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."

Beef Industry Is Not Amused

The beef industry, not surprisingly, does not accept the results of these studies.

These studies oversimplify the complex production of beef, the industry says. "The U.S. beef industry produces beef with lower greenhouse gas emissions than any other country," an industry statement reads.

Harmful gas emissions from developed countries such as the United States have been falling since 1970. Developing countries have more than doubled their emissions. These poorer countries are eating more beef.

Beef cattle produced more than half the emissions. Dairy cattle were responsible for 17 percent, sheep 9 percent, buffalo 7 percent, pigs 5 percent and goats 4 percent. The largest increases came in Congo, the Central African Republic and Oman, the study found. The study estimated production of greenhouse gases in 237 countries.

"More and more of the developing world is adopting the bad habits of the developed world," said study co-author Ken Caldeira.

Careful With The Resources

The other study, from the Proceedings of the National Academy of Sciences, focused on the industrialized food chain in the United States. This study looked at grazing, growing food for the cattle, and the use of irrigation water.

The study should not just guide consumer choice, but also government policy, Eshel said.

He said this issue is an example of the "tragedy of the commons," where people each selfishly use a common resource. Eventually, the resource runs out.