Bolinas, Calif.

IS eating a hamburger the global warming equivalent of driving a Hummer? This week an article in The Times of London carried a headline that blared: “Give Up Meat to Save the Planet.” Former Vice President Al Gore, who has made climate change his signature issue, has even been assailed for omnivorous eating by animal rights activists.

It’s true that food production is an important contributor to climate change. And the claim that meat (especially beef) is closely linked to global warming has received some credible backing, including by the United Nations and University of Chicago. Both institutions have issued reports that have been widely summarized as condemning meat-eating.

But that’s an overly simplistic conclusion to draw from the research. To a rancher like me, who raises cattle, goats and turkeys the traditional way (on grass), the studies show only that the prevailing methods of producing meat  that is, crowding animals together in factory farms, storing their waste in giant lagoons and cutting down forests to grow crops to feed them  cause substantial greenhouse gases. It could be, in fact, that a conscientious meat eater may have a more environmentally friendly diet than your average vegetarian.

So what is the real story of meat’s connection to global warming? Answering the question requires examining the individual greenhouse gases involved: carbon dioxide, methane and nitrous oxides.