If you haven’t followed the controversy over “pink slime,” here’s the short version. For years, meat producers have been recovering scraps from cow carcasses, centrifuging out the fat, treating the remains with ammonia gas to kill bacteria, and using it as a filler in products such as ground beef.

This supermarket is going slime-free. But is that such a good thing? (ALEX GALLARDO/REUTERS)

It’s possible. Over at the Atlantic, New York University’s Marion Nestle explains that the reliance on lean finely textured beef (or LFTB for short) is a way for the beef industry to get more use out of each cow that gets slaughtered:

For one thing, it solves an enormous problem for meat producers. Only about half the weight of the 34 million cattle slaughtered each year is considered fit for human consumption. The rest has to be burned, buried in landfills, or sold cheaply for fertilizer or pet food.

LFTB recovers 10 to 12 pounds of edible lean beef from every animal and is said to save another 1.5 million animals from slaughter.

If those numbers are correct — and, fair warning, they appear to come from the beef industry — then a ban on pink slime could, potentially, require the slaughter of another 1.5 million cows to maintain current levels of beef consumption. And, because cows are a major source of heat-trapping methane (all that burping), that could have a serious climate impact.

How much impact? We can do a rough calculation. The average cow emits the equivalent of about four tons of carbon dioxide per year. To put that in perspective, the average automobile emits about five tons per year. So, in the worst case, a total ban on pink slime would be like adding 1.2 million cars to the road, from a global-warming perspective.

But that’s assuming beef consumption remains constant. One thing this whole exercise highlights is the outsized impact that meat-eating in general has on climate pollution. One 2006 study from the University of Chicago’s Gidon Eshel estimated that if all Americans switched to a vegan diet, the nation’s heat-trapping greenhouse gas emissions would drop by 6 percent or more. (That’s unlikely in the near future, but it’s worth noting that U.S. meat consumption has been on a steady decline for the past 20 years, in part because American diets seem to be increasingly eco-conscious.)

And, granted, there are many other issues when it comes to lean finely textured beef. There’s still controversy over whether the process for making the stuff truly eliminates all pathogens — see Tom Philpott’s report for more on that. There’s the much broader debate about the downsides of industrialized meat production. And Nestle brings up some cultural concerns: “Do we want LFTB in our food? Or do we and our children deserve better? Serving healthy and delicious food is a way to show respect for our culture, food, children, and schools, and to invest in the future of our nation.” All fair questions. But that doesn’t mean there won’t be costs, as well.

Update: Kevin Drum is suspicious of one of the underyling assumptions here — namely, that banning pink slime would lead to an additional 1.5 million cows being slaughtered. He cycles through a whole bunch of studies and numbers and argues that the effect would be “maybe a third of what the industry claims.” (In that case, banning pink slime would be the equivalent to, at worst, adding 300,000 to 400,000 cars to the road.) Go read his post for a fuller explanation.