In a Cow's Stomach, Novel Approach to Warming New Zealand's contribution to global warming comes from an unlikely source: burping farm animals. Scientists say one way to cut down on greenhouse gases is to remove a methane-producing microbe in cows and sheep.
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In a Cow's Stomach, Novel Approach to Warming

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In a Cow's Stomach, Novel Approach to Warming

In a Cow's Stomach, Novel Approach to Warming

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  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
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Now to Climate Connections, our series with National Geographic on climate change. This month, we focus on the Pacific. Today, we go to New Zealand. It's worth knowing as we head there that most industrial nations are reducing the amount of greenhouse gasses from power plants and factories.

In New Zealand, a third of these gasses come from animals in the form of methane gas. So researchers are trying to lower greenhouse gas hoof prints by changing what goes on inside the stomachs of millions of sheep and cows.

NPR's Christopher Joyce reports from New Zealand.

CHRISTOPHER JOYCE: The north island of New Zealand is a windy place. Here, just outside the city of Palmerston North, is the Taraua Wind Farm. There are literally hundreds of huge wind turbines up here on a ridge that overlooks the city.

This is a solution to some of New Zealand's problem with greenhouse gases. However, the real problem in New Zealand is right underneath these wind turbines: it's sheep and cows - livestock produces methane.

(Soundbite of cows mooing)

Dr. HARRY CLARK (Animal Scientist, AgResearch): I'm Harry Clark. I'm an animal scientist who works for a leading research institute, AgResearch, and I'm in charge of a program that is trying to reduce methane emissions from ruminant animals.

JOYCE: Harry Clark spends much of his time in a big shed at Massey University in the company of a few dozen cows...

(Soundbite of sheep)

JOYCE: ...and some sheep, too. These animals don't know it, but they have a gas problem. Methane - molecule for molecule - warms the planet 20 times more than carbon dioxide. A ruminant animal creates a lot of it when it digests food in its rumen - a part of its digestive system that works like a fermentation tank.

Here's how it works: The rumen is kind of a zoo, really, overrun with about 400 kinds of microbes. These microbes break down whatever the animal eats so it can digest it. One of these microbes specializes in making methane.

Dr. CLARK: And that methane, then, is either burped out or it gets absorbed into the bloodstream and then breathed out through the lungs.

JOYCE: So we should establish it's not cow farts.

Dr. CLARK: It's a lovely headline, but I'm afraid it's biologically incorrect.

JOYCE: The correct fact is 95 percent of the methane comes out of the animal's mouth. It goes up into the atmosphere and warms the climate. So how can scientists put a stop to this gas problem? Well, maybe by getting rid of those bugs. Harry Clark's colleague, Ron Reimus, says they can't see any reason to keep those methane microbes inside the animals.

Dr. RON REIMUS (Animal Scientist, AgResearch): We feel that because they're not absolutely required for survival, that you could get rid of them.

JOYCE: One strategy is to genetically engineer the microbes so they won't make methane. Another is to give the sheep and cows some kind of feed that these bugs don't like - so long, of course, as that doesn't affect what's most important to New Zealand farmers, like Graeme Maybey.

Mr. GRAEME MAYBEY (Farmer): I live in Woodville, which is in the north island of New Zealand. And we run a 500-acre dairy farm, milking 350 cows.

JOYCE: Maybey farms the same land his parents did. He says farmers in New Zealand are aware that methane can warm the planet, and they're not against altering livestock to do something about that methane.

Mr. MAYBEY: If we can reduce the release of methane in our cattle, as long as it's not going to affect production of milk and meat, then yeah, we're all for it.

(Soundbite of clanking sound, footsteps)

JOYCE: And that's what Clark's research team is trying to do. They measure everything the livestock eat, how much milk they give and how much they weigh. And, most important, says Clark, they measure how much methane is coming out of them.

Dr. CLARK: As you can see, we're now fitting a halter over the animal's head, which allows us to keep him positioned - the collection pipe over its nose so that we ensure that we're collecting a representative sample from its breath.

JOYCE: A plastic contraption partially covers a cow's nose and carries its exhalations through a tube and then to a collector. Clark and his team measure changes in methane when they alter the microbes in its gut, or when they give the cow a new kind of feed, for example.

What Clark hopes is that once the methane-making microbes are gone, the energy they consumed will stay in the cow or sheep and help it produce more milk or meat.

Dr. CLARK: New Zealand relies on the agriculture sector for its livelihood. So anything we do to stop methane has got to be done without detriment to the product and to the animal. I mean, that's a given.

JOYCE: The scientists at Massey University aren't there yet, but if they say if they can figure out how to do all this, well, there are a lot of countries in the world that might be willing to pay New Zealand to solve their gas problems.

(Soundbite of cow mooing)

JOYCE: Christopher Joyce, NPR News.

(Soundbite of sheep)

MONTAGNE: You can find our other climate change stories at Check out the latest episode of our animated series. It's all about carbon from NPR's Robert Krulwich and Public Television's "Wild Chronicles."

(Soundbite of music)


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