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Public Radio's Environmental News Magazine (follow us on Google News)

Lower-Emitting Livestock

Air Date: Week of

Sheep and other livestock are the source of New Zealand’s biggest greenhouse gas problem. (Photo: Kurt Weyerhauser)

In order to meet its Kyoto Protocol obligations, New Zealand must find a way to limit greenhouse gases from its biggest contributors - sheep and cattle. Mark Aspin of the Pastoral Greenhouse Gas Research Consortium is developing livestock that produce less methane. Host Bruce Gellerman talks with Aspin about New Zealand's environmental challenge, given its 40 million greenhouse-gassy sheep.


GELLERMAN: It’s Living on Earth, I’m Bruce Gellerman.

Global warming skeptics argue that people aren't to blame for causing climate change and maybe they have something: sheep, cows, and farmed deer are also doing their part to warm up the planet. It seems the animals emit two of the most powerful greenhouse gases. And in a place like New Zealand, where they raise 40 million sheep, 10 million cows, and a million deer, developing less gassy farm animals is a national priority. There are 25 full-time researchers working at the Pastoral Greenhouse Gas Research Consortium in Wellington. Mark Aspin manages the project. Welcome to Living on Earth.

ASPIN: It’s nice to be here.

GELLERMAN: Mr. Aspin, I understand you grew up on a farm. Is that right?

ASPIN: Yes, I have, yup.

GELLERMAN: So you were very familiar with this problem for a long time.

ASPIN: Well, I was in farming, dairy farming and sheep farming for some years, but I didn’t realize we were producing methane and nitrous oxide, which are greenhouse gases. So I’m familiar with farming livestock, yes. And ruminant animals which sheep, cattle, and deer are when they digest forage in their first stomach, the rumen, have a bi-product of methane, one of the major greenhouse gases. And also, the urine and dung that’s excreted out the other end can lead to nitrous oxide, which is also a greenhouse gas.

GELLERMAN: Forgive me if this is not a polite question, I’m not sure how to ask it, but is the problem belching or is it flatulence?

ASPIN: It’s belching. What actually happens is in the fore-stomach of a ruminant animal there’s a big bag where you’ve got lots of microbes. And the animals graze and eat their forage, chew it, and inside that first stomach there’s basically a big fermentation occurring breaking down all the plant material so that the animal can get the nutrients from it.

Most of the methane emitted by sheep actually comes through their mouths. (Photo: Christine Macintyre)

And as a bi-product of that fermentation, hydrogen is produced and CO2 and there’s a small organism that’s part of their ecosystem known as a methanogen which takes those two products, hydrogen and CO2, and combines it and creates CH4 which is methane and that’s belched out. So, periodically the animal belches methane out as the fermentation occurs. So it’s an ecological system that’s been in existence for hundreds and thousands, perhaps millions, of years and we’re wanting to try and see whether we can alter it somewhat.

GELLERMAN: I’m sure you’ve heard every joke there’s possibly could be made about this and, uh, but it’s –

ASPIN: No, I’ve never, you’ve never heard every joke. [LAUGHTER] I’ve heard plenty.

GELLERMAN: But this is a very real problem.

ASPIN: Well it’s a real problem and there’s a lot more cattle and sheep around the world than there is in New Zealand so it’s not just our problem it’s an international issue and you’ll find in most developing countries large numbers of livestock. Livestock account for about 14 percent of global greenhouse gas emissions so it’s not insignificant in numbers. Um, the issue for New Zealand is that we’ve got an economy strongly built around agriculture and that means that we have about 48 percent of our total greenhouse gas emissions come from agriculture, from methane and nitrous oxide. We’re unique as a developed country in that we’ve got such a strong profile for agricultural greenhouse gases as opposed to more developed, other developed countries that have a lot more coal and energy greenhouse gas emissions.

GELLERMAN: Now you’re under the gun because, you know, according to the Kyoto agreement you’ve got to reduce very significantly emissions by, what, 2012.

ASPIN: And now I’m talking to the U.S. Yes we’ve got to reduce our emissions back to 1990 levels so that for New Zealand is about a 20 to 25 percent reduction across our whole economy. And here we face a significant carbon cost in the future and that’s the reason that the country and the industry has engaged in research to try and see whether we can mitigate that problem and reduce that cost.

GELLERMAN: So where is the most fruitful part of your research taking you? Where do you think you can really make significant cuts?

Sheep and other livestock are the source of New Zealand’s biggest greenhouse gas problem. (Photo: Kurt Weyerhauser)

ASPIN: There are some products available that can actually reduce nitrous oxide 30 to 40 percent and methane solutions are, uh, we don’t have one here today for methane we think we’re still five years away from a solution and probably some years after that before we get widespread adoption amongst our livestock farmers. Our science has taken us into just really discovering and understanding the microbes and how they interact and we recently completed the genome sequence of the rumen major mathanogens, which gives us in a sense a blueprint or a parts list of the organism. And the layout has to be a bit more targeted in their approaches as we go forward.

GELLERMAN: What about cloning? I mean, we’ve cloned a sheep, Dolly the sheep. Could you clone a sheep that wouldn’t, well, fart?

ASPIN: Well, certainly that’s not an avenue that we’ve been looking at. We’re using traditional and natural methods of reproduction. We have been looking at animal selection to see whether we can find high and low emitting sheep or cattle and then perhaps if we can identify those animals and breed from them, that’s a long term solution that’s part of our approach to this issue as well.

GELLERMAN: Yeah, and Prime Minister Helen Clark has set as a national goal of New Zealand to become the world’s first carbon neutral country.

ASPIN: I wouldn’t want to comment on that. Yeah I actually she certainly has said that so here we’re pretty conscious about trying to be, do the right thing. We only account for .2 percent of the world’s greenhouse gases emissions. So we’re very small in the global scale but we’d like to believe that we can still be leaders and do the right thing.

GELLERMAN: Well Mr. Aspin I want to thank you very much. I really appreciate your time.

ASPIN: Ah you’re welcome and haere ra.

GELLERMAN: Hi dee grah?

ASPIN: Haere ra, it’s just farewell.

GELLERMAN: Well, haere ra, Mr. Aspin.

ASPIN: That’s alright.

GELLERMAN: Mark Aspin manages the Pastoral Greenhouse Gas Research Consortium in Wellington New Zealand, which is trying to cap global warming coming from sheep, cows, and deer.



The Pastoral Greenhouse Gas Research Consortium


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