There has long been debate about meat and its role in consumption of resources. A recent New York Times op-ed column posits the notion that soybeans, often toted as the more eco-friendly protein source, might actually do the planet more harm than traditionally grazed livestock.

Author Nicolette Hahn Niman, a livestock rancher herself, discusses the credible arguments against hamburger. But, she points out, the greatest detriment comes from animals housed in Concentrated Animal Feeding Operations (CAFOs). These operations, she writes, "[crowd] animals together in factory farms, [store] their waste in giant lagoons and [cut] down forests to grow crops to feed them [and] cause substantial greenhouse gases." Niman continues to discuss meat and its relation to carbon dioxide, methane, and nitrous oxides.

Niman reminds readers that farming equipment burns most agricultural CO2 in America, but in the rest of the world, deforestation is the big CO2 culprit. Further, much of this international deforestation is done for soybean cultivation. Brazil, for instance, dedicates about "70 percent of areas newly cleared for agriculture ... to grow soybeans." Much of this soy goes into making food for livestock in CAFOs, but it's also used to make the world's tofu, the dietary staple of many vegetarians.

Traditional farms don't have much to do with this CO2 cycle, Niman says, because they tend to grow their own soy and keep their animals outside, using less machinery than major agribusiness.

As for methane, agriculture's "second-largest greenhouse gas," Niman points out that rice fields are huge generators of this gas, as are the liquid manure concoctions Americans produce and pump all over their corn and soy crops ... but traditional farms with grazing livestock aren't really culprits in this planetary problem. Animals on these farms fertilize the land naturally. Niman points out that individuals can cut back on their carbon and methane footprints just by purchasing meat from grazed animals. The article points to research at Australia's University of New England and the University of Louisiana, which indicates that poor diets contribute even more to methane produced in industrialized animal operations.

Niman continues her defense of meat in exploring nitrous oxide, which, again, seems to come mainly from man-made fertilizers on industrial farms. Organic meats (and other crops for that matter) are free from chemical fertilizers and, thus, are not contributors to the problematic levels of nitrous oxide. She goes on to point out the benefit in grazing land, citing research from Kansas State University and North Dakota State University, that indicates grazing animals are key to healthy prairies and increased vegetation. Other benefits include decreased erosion, and improved water quality.

The piece concludes by reminding us that transportation of food is as much of a problem as its production, and that eating seasonal, local foods (including meat that was raised traditionally) can not only decrease a person's greenhouse gas contribution, but actually help to improve ecosystems. "None of us, whether we are vegan or omnivore, can entirely avoid foods that play a role in global warming," says Niman. But if we avoid processed foods, buy locally and seasonally, and cut back our intake of meat, making sure it's from traditionally raised animals, "It could be, in fact, that a conscientious meat eater may have a more environmentally friendly diet than your average vegetarian."

Also on MNN: 

• Study says meat production creates half of all climate change emissions. (Plus: View the original report.)