Manure, methane and McGovern
In a Web forum for presidential candidates in September, TV talk-show host Bill Maher asked former Sen. John Edwards a snarky question: Because Edwards had suggested that people trade in their SUVs to benefit the environment, and cattle generate more greenhouse gases than SUVs, "You want to take a shot at meat?" Maher asked.
Edwards wisely dodged the question. It is extremely hazardous for politicians to take on the U.S. beef industry, a lesson learned by Sen. George McGovern in the late 1970s when his Select Committee on Nutrition dared to recommend that Americans cut down on red meat and fatty dairy products for health reasons. After a ferocious lobbying blitz from meat and dairy interests, the committee rewrote its guidelines to suggest diners simply choose lean meats that "will reduce saturated fat intake." McGovern was voted out of office in 1980, in part because of opposition from cattlemen in his home state of South Dakota.
Beyond the dangers of taking on the beef bloc, legislating food choices is an unpopular and nearly impossible task, so it's unlikely any candidate will endorse a national vegetarian movement to fight global warming any time soon. There are other approaches, though.
Cows and other ruminants have four stomachs, the first of which, called the rumen, is where the trouble lies; bacteria in the rumen produce methane. Scientists -- mostly in Australia, New Zealand and Britain, where the problem is taken a lot more seriously than it is here -- are working on a variety of technical solutions, including a kind of bovine Alka-Seltzer. Scientists are also trying to develop new varieties of feed grasses that are more energy efficient and thus generate less methane, and they are experimenting with targeted breeding to produce a less-gassy strain of cattle.
But it's not just about the belching. Livestock manure also emits methane (especially when it's stored in lagoons) and nitrous oxide, better known as laughing gas. There's nothing funny about this gas: It has 296 times the warming potential of carbon dioxide, and livestock are its leading anthropogenic (human-caused) source. The best way to reduce these gases is to better manage the manure; storage methods and temperature can make a big difference. The California Air Resources Board is studying manure-management practices as part of a sweeping effort to identify ways of cutting greenhouse-gas emissions, work that by the end of next year might lead to regulation of the state's ranches and dairies. Other states should do the same.
