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Grass-fed beef may be one of the worst contributors to global warming

One study shows grass-fed cattle may be even worse for the environment than cattle from industrial feedlots

I’ve been a die-hard carnivore most of my life. The sight of my grandfather throwing thick New York strips onto his small grill is one of my fondest memories. Sharpening my culinary skills as an adult, I regularly gorged on grass-fed steaks, grilled just like my grandfather’s, and imagined myself carrying on the legacy of our Stone Age ancestors.

Like many Americans, eating beef was something I loved and celebrated — at least until I started spending long car rides with my producer, a vegan. The subject of eating animals turned out to be a touchy one during our many hours on the road for America Tonight, and I learned to refrain from offering my latest technique to extract the marrow from cow bones.

Cattle are an American icon, brought to market by cowboys on the range. Americans consume about 25 billion pounds of beef annually, and to meet that demand, 31 million cattle are slaughtered in the United States every year. But it wasn’t just my detailed description of freshly slaughtered flesh that my producer found disturbing. It was a concern for the environmental impact that beef production was causing.

As it turns out, he isn’t alone. Experts at this year’s climate summit in Paris say that livestock production accounts for about 15 percent of global greenhouse gases. Gidon Eshel, a research professor of environmental physics at Bard College, published a groundbreaking paper last year on the impact of livestock production on climate change. Among his findings: a fixed number of calories from beef has a far greater impact on global warming than an equivalent number of calories from pork, chicken, milk or eggs.

In other words, all that beef has come at a steep cost to the environment.

With Americans consuming about 25 billion pounds of beef each year, it has come at a steep price for the environment.
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Livestock production is one of the biggest contributors to greenhouse gas emissions, worse than all the world’s transportation combined, and according to Eshel, the biggest offenders on the farm are cattle.

“Beef is in a category entirely by itself,” Eshel says, “at least an order of magnitude more greenhouse gas intensive than the other categories, sometimes more like 25-fold more.”

The problem began decades ago, when, to meet the growing appetite for beef, American cattle producers turned to an industrial feed-lot system, in which cows and steers spend the final few months before slaughter fattening up on a diet of soy and corn.

The vast majority of American cattle still come from feed-lots, but in recent years some American consumers have started opting for grass-fed beef, from cattle that spend their entire lives on pastureland.

But that grass-fed option, while it sounds more natural, Eshel says, can have an even bigger impact on the environment because of how much cows burp. The problem comes from methane, a greenhouse gas that is about 25 times more potent than carbon dioxide. Cattle raised exclusively on grass produce about twice as much methane, Eshel said, because they burp far more from grass than from corn and soy.

“What's called grass-fed in the Midwest was the single worst option in terms of global warming,” Eshel says.

The industrial diet of corn and soy might make cattle mortally ill, Eshel says, but in terms of climate impact, it’s actually more efficient. 

What's called grass-fed in the Midwest was the single worst option in terms of global warming.

Gidon Eshel

Bard College

But one grass-fed beef producer, Ken Jaffe, disagrees. Ten years ago, Jaffe left his life as a family medical doctor in Brooklyn to establish Slope Farms, a grass-fed cattle ranch in upstate New York. He sells what he calls “a superior product” to high-end restaurants and specialty markets.

“We’re not using any herbicides. We’re not using any pesticides. We're not using any chemical fertilizers,” he said. “This is a self-nourishing system. The sun makes the grass grow. The cattle harvest the grass. The cattle fertilize the grass, and all we have to do is just move them to the next pasture.”

Jaffe said that this grass-fed model works for the consumers too.

“It tastes better, it has a healthier fat profile. These animals are living a better life for beef, for cattle because they're living what is a more cattle-like existence," he said. "They're outside. They're grazing. This is what cattle were genetically designed to do."

Eshel said he appreciates Jaffe’s connection to the animals. Having grown up on a farm in Israel, he raised cattle for beef, but says he gave up eating beef when, as a scientist, he crunched the data and recognized the cost to the environment.          

“I'm not opining about their happiness, I'm opining about the greenhouse gas emissions,” Eshel said. “If your objective is really to produce most efficiently the most beef you can, the corn route is more efficient.”  

But Ken Jaffe says the environmental impact depends on the quality of the pasture.

“If you're feeding cattle really crappy grass – older, more fibrous grass – then you get more methane produced,” he said, looking over his pasture in Upstate New York. “But if you compare the production of high-quality multi-species grass with a good amount of legumes in it, which we have here, and which you can produce by just promoting perennial pasture, it's much less so.”

The vast majority of American cattle still come from feed-lots, but in recent years some American consumers have started opting for grass-fed beef.
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The key variable for Jaffe is something called carbon sequestration: Jaffe says that by allowing his land to be used as pasture, he encourages this process, therefore mitigating the damage caused by methane emissions.

“The wildcard in this is the carbon sequestration, which is how much carbon we are taking out of the atmosphere and putting into the ground by producing a grassland, which is prairie-like," he said.

But Eshel dismisses the offset of carbon sequestration, saying it was insignificant when compared to the scale of global warming.

“What's the length of time this carbon is going to remain sequestered in the soil and not return as gas to the atmosphere? The answer is a year to 10 years. In very rare cases, it’s a century," he said. "That's not the scale of the problem. If we stopped emitting anything right now, it would take almost a million years for the earth to readjust to where we started from before the industrial revolution."

Consumers should reconsider their choice to eat beef, and not just because of the significant impact on the environment, says Jenny Brown, who runs the Woodstock Farm Sanctuary, along New York’s Hudson Valley, a couple of hours from Jaffe’s farm. The sanctuary provides a refuge for 300 animals that have escaped or have been rescued from slaughterhouses and farms.

“If we say we love animals and we have compassion and we don't want them to suffer, we need to look at our consumer choices,” Brown said.

She founded the Sanctuary 12 years ago because she is ethically opposed to the eating of animals.

“Any step we can take in the direction of shifting away from consuming animals and animal products is a step in the right direction, even if you're just doing it for yourself, for your health and for the planet," she said. "Those are good reasons, too. I do it for the animals. “

This story was produced by George Lerner (@geolerner).

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