A year later, two now widely quoted studies were published that pushed aside the fairly obscure academic papers they corroborated: University of Chicago geophysicists Eshel and Martin produced an econometric analysis of U.S. emissions, and the U.N. Food and Agriculture Organization released its global analysis, "Livestock's Long Shadow." They used very different data sets and approaches, but both made a strong case that the food system (broadly defined) contributed more to climate change than the transportation sector. Weren't our cars the main culprits? How could the food system matter more?

An ideological war thus engaged. On one side, vegetarian and animal rights activists had a new reason to call on consumers to shun meat. On the other were individuals who saw these calls as attacks on their personal right to eat whatever they wanted. And the beef industry—for a while anyway—was absent from the debate.

The beef industry is silent no more. Voluntary rancher fees from an industry association's advocacy program have underwritten pro-meat marketing campaigns, stipends for researchers to raise doubts (but not conclusive evidence) about scientific studies, and dissemination of talking points that are misleading at best. "Reducing intakes of meat and dairy would only lead to hunger," I read recently, and the headline of an industry newsletter stated, "Meat and dairy intakes not linked to climate change." These news items represent a disturbing trend: raise doubts, obfuscate the facts, and misinform.

I debated a rancher on Fox News in January 2009 who claimed that his cows didn't contribute to global warming "because they eat grass." This is similar to a claim put forth in a grass-fed cattle rancher's newsletter that his beef "is carbon neutral" because cows "are part of the carbon cycle. ... They are born, they eat, they die, they return to the soil." Well, so are humans, and our choices matter too. There are lots of reasons to support small-scale, pasture-raised beef versus CAFO-produced, but carbon neutrality sure isn't one of them.

The FAO report held livestock emissions responsible for 18 percent of global greenhouse gases, more than the transportation sector. This percentage has been criticized recently as being too high. The FAO is re-evaluating its calculations—for the transportation sector—in response to complaints that they were understated. In other words, despite the headlines that would have you believe otherwise, what's at stake are the livestock and transportation sectors' relative percentage contributions to climate change, not the total amount of livestock emissions. Perhaps our cars are equally culpable, but where's the good news in that conclusion?

I applaud the ranchers who are genuinely working to improve waste management (the biggest variable in emissions) or trying different animal forages that might lead to fewer emissions (nothing is yet conclusive). But an increasing number of independent studies continue to show that beef imposes a higher climate-change burden than plant-based foods we can eat directly, regardless of production methods (pasture- or feedlot-based) or many ranchers' honest efforts at land stewardship. One study equated the emissions associated with each American's three and a half pounds of weekly meat consumption with the emissions of driving an efficient car 200 miles.