Methane Emissions

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7:27 min.

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Summary

Methane is perhaps most familiar to us as the main component of natural gas. Though present in the atmosphere at very low concentrations, it is a comparatively powerful greenhouse gas: one kilogram of methane has 21 times the warming effect of the same amount of carbon dioxide. The concentration of methane in the atmosphere is increasing annually. Globally, agriculture is a prominent source of methane. Much of the methane produced on farms is from cattle and sheep. Agriculture and Agri-Food Canada scientists are studying what the cow is eating to make it more environmentally friendly, with some interesting findings.

Transcript of Video

Jane Gilbert
But first, putting a lid on global warming. Today, the United States signed a major international treaty on global warming. The US put its signature on the Kyoto Accord, which calls for sharp reductions of greenhouse gases by 38 industrialized countries. Now most of those gases come about as the result of burning fossil fuels. However, a small but significant part of the problem comes from animals, and the methane gas they produce. Tonight on Earth Tones, how scientists are trying to control the gases that come out of cows by changing what goes in.

Jay Ingram
The ONLY job these beef cattle have is to eat lots and grow fast. And now, after a summer of grazing, they weigh more than 500 kilos apiece. The problem is, all that eating produces lots of methane.

Paul McCaughey
World-wide, cattle produce enormous quantities of methane. Probably about 15 percent of the world-wide emissions of methane. Individual cattle can produce about 65 kilograms of methane per year.

Jay Ingram
An individual dairy cow produces almost twice that amount because they eat more. When cows eat, they also belch. It's easy to miss... just a tiny shudder. Looks innocent enough but imagine 1.3 BILLION cattle around the world, all belching, all day long, and you get an idea how big the problem is.

Jay Ingram
Methane exists in much smaller quantities than carbon dioxide in the atmosphere. But kilo for kilo, it has 21 times the warming effect. And it's increasing at a faster rate.

Paul McCaughey
The methane concentrations are increasing at about one percent per year, compared with about half a per cent per year for carbon dioxide. And there's concern that eventually methane is going to become a major problem. In fact, the major problem.

Jay Ingram
Although it's a small part of the total global warming picture, ALL plant-eating animals produce methane naturally. Humans account for almost half a per cent of total animal emissions. Wild animals combined produce roughly five percent. Sheep and goats more still. But cattle contribute a whopping 71 percent to the total.

Jay Ingram
At the University of Manitoba, they study the inner workings of the cow's stomach. This research cow has been fitted with a plastic cap, a window on its digestive processes.

Karen Wittenberg
You just heard what is probably the release of a litre or two litres of gas which normally the cow would be belching or exhaling but because of the presence of the window, it's being released this way.

Jay Ingram
The cap doesn't hurt the cow. This one has lived with it for five years. The cap goes straight into her first stomach, called the rumen. It's basically a big fermentation vat ... churning hay while she eats.

Karen Wittenberg
And what you see here is that same hay after it's been ingested by the animal and after some of the bacteria -- the microbes in the rumen -- have started to digest it and ferment it.

Jay Ingram
Deep in the stomach, juices help convert the hay into energy. Dr. Wittenburg can reach right down and pull out a sample.

Karen Wittenberg
And you can see it's much more liquid. Each drop contains millions and millions of bacteria, fungi, and protozoa. All working to break this down into an energy and protein source for the cow.

Jay Ingram
The bacteria in that fluid show up under the microscope. The ones that produce methane are very small.

Karen Wittenberg
We commonly call them methanogenesinor. About a billion to a hundred billion per millilitre of rumen fluid. They're very small, you might see something of this nature here. They're not very clear here but they're the ones that take up the hydrogen gas and produce methane.

Jay Ingram
Researchers have discovered that about 85 percent of the methane comes out the mouth and nose. The rest travels through the large intestine and is released from the back end of the animal.

Jay Ingram
With that in mind, researchers have found a way to measure methane from the front end while the cow grazes. The stainless steel canister hanging from his neck has had all the air vacuum-pumped out of it. A narrow tube in front of the cow's nose draws air samples down into the canister.

Paul McCaughey
When the cow belches, a little bit of the gas gets pulled into this container and that happens continuously over a 24-hour period.

Jay Ingram
For the past four years, they've been experimenting with different types of feed, comparing methane emissions from each.

Jay Ingram
Dairy cows have also been tested. The methane measurements have to be very precise.

Jay Ingram
This is the other part of the measurement process. A tiny capsule filled with a man-made gas called sulfur hexafluoride or SF6. It's placed in the cow's rumen, where the gas is released at a steady, carefully pre-determined rate. The SF6 tracer gas will mix with the methane in the cow's stomach. Samples of BOTH gases end up in the canister.

Jay Ingram
The samples are sent through a gas chromatograph. This machine measures the ratio of the two gases. And from this ratio, total methane output can be calculated.

Jay Ingram
What they've found is that methane levels drop when the cow eats high-quality feed that's easy to digest.

Karen Wittenberg
Our pasture trials have shown that animals on alfalfa-based pastures produce more with less methane production than animals that are on grass-based pastures.

Jay Ingram
In fact, methane emissions dropped 10 percent when alfalfa was mixed in with the grass.

Jay Ingram
The age of the grass also makes a difference. When dairy cows were fed younger grass, they also produced less methane.

Jay Ingram
So if farmers can be encouraged to use top-quality feed, then everyone benefits. The cow. The environment. Even the farmer.

Karen Wittenberg
Methane is an energy loss to the cow and if we can somehow reduce methane production then we can improve the bottom line and make cattle production more profitable for farmers. So that would be a win-win situation both for society and for the farmer.

Jane Gilbert
Tonight's edition of Earth Tones was produced along with Agriculture and Agri-Food Canada.