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Category — Methane Emissions

Quick fixes won’t solve CO2 danger

Tim Radford


Bleak outlook: smoke billows from an oil-fired power station in Sweden. Image: Mikeinc via Wikimedia Commons

New research backs up the growing body of evidence that the only way to limit global warming in the long term is a serious cut in carbon dioxide emissions from burning fossil fuels.

Once again, US scientists have come to the same conclusion: there really is no alternative. The only way to contain climate change and limit global warming, they say, is to reduce carbon dioxide emissions.

It won’t really help to concentrate on limiting methane emissions, or even potent greenhouse gases such as hydrofluorcarbons, or nitrous oxide, or the soot and black carbon that also contribute to global warming. Containing all or any of them would make a temporary difference, but the only thing that can work in the long run is a serious cut in carbon dioxide emissions.

Raymond Pierrehumbert, a climatologist at the University of Chicago, combined new research and analysis and a review of the scientific literature. He reports in the Annual Review of Earth and Planetary Sciences that although livestock emissions such as methane are – molecule for molecule – potentially more potent as global warming agents than carbon dioxide, there remains no substitute for reducing the burning of fossil fuels.

“Until we do something about CO2, nothing we do about methane or these other things is going to matter much for climate,” he said. [Read more →]

July 7, 2014   No Comments

Wetland emissions mean more methane

Alex Kirby


More methane is leaking from tundra and other high-latitude environments than scientists had realized. Image: Kat Spence via Wikimedia Commons

Methane emissions are rising globally because wetlands – especially in northern latitudes – are releasing more than anyone had realised, a team of researchers based in Canada says.

The bad news is that global emissions of methane appear to be rising. The worse news is that scientists believe there’s much more to come in the form of releases from many of the world’s wetlands.

Methane is emitted from agriculture and fossil fuel use, as well as natural sources such as microbes in saturated wetland soils. It is a powerful greenhouse gas, and in the short term it does much more damage than the far more abundant carbon dioxide.

Just how much more damaging it is is something scientists keep updating. There is now international agreement that methane is 34 times more potent than CO2 over a century, but 84 times more over a much shorter timespan – just 20 years. And two decades can be crucial in trying to slow the rate of climate change.

Professor Merritt Turetsky, of the department of integrative biology at the University of Guelph, Canada, is the lead author of a paper published in the journal Global Change Biology.

The paper is based on an analysis of global methane emissions examining almost 20,000 field data measurements collected from 70 sites across Arctic, temperate and tropical regions. [Read more →]

May 2, 2014   No Comments

Warmer freshwater emits more methane

Tim Radford


Swamps, marshes, rice paddies and other freshwater ecosystems are sources of methane. Image: By vastateparksstaff (Uploaded by AlbertHerring) via Wikimedia Commons

Scientists think the amount of methane emitted to the atmosphere from freshwater ecosystems will increase as the climate warms, triggering further warming.

British scientists have identified yet another twist to the threat of global warming. Any further rises in temperature are likely to accelerate the release of methane from rivers, lakes, deltas, bogs, swamps, marshlands and rice paddy fields.

Methane or natural gas is a greenhouse gas. Weight for weight, it is more than 20 times more potent than carbon dioxide over a century, and researchers have repeatedly examined the contribution of natural gas emitted by ruminant cattle to global warming. But Gabriel Yvon-Durocher of the University of Exeter and colleagues considered something wider: the pattern of response to temperature in those natural ecosystems that are home to microbes that release methane.

They report in Nature that they looked at data from hundreds of field surveys and laboratory experiments to explore the speed at which the flow of methane increased with temperature.

Microbes, algae, freshwater plants and animals are all part of an active ecosystem and take their nourishment from and return waste to the atmosphere. Healthy plants take carbon dioxide from the atmosphere with photosynthesis. Most of the methane in freshwater systems is produced by an important group of microbes called Archaea that live in waterlogged, oxygen-free sediments and play an important role in decay. [Read more →]

March 23, 2014   No Comments

Low-flatulence livestock can cool planet

Tim Radford


Eating for a cooler world? Animals’ diets are one factor that could cut methane emissions. Image: Courtesy of Yaron P

Farmers may be able to rear livestock which produce fewer emissions from their stomachs of methane, one of the most important greenhouse gases.

Stand by for a new breed of farm animal – the low-methane cow. European scientists are collaborating in a bid to find a cow that makes the same milk, but manages to do so while emitting lower levels of natural gas from the ruminant stomach.

Methane is a fact of farm life: cows eat grass, hay and silage, and then proceed to digest it with help from an arsenal of stomach and gut microbes. But methane is also a potent greenhouse gas (GHG): weight for weight it is more than 20 times more potent than carbon dioxide over a century.

About a fifth of all GHG emissions from agriculture are directly released from the stomachs of the world’s cattle herds. And a consortium called RuminOmics has launched research into every aspect of animal husbandry in an attempt to lower the methane productivity while keeping up the dairy output.

Phil Garnsworthy is a dairy scientist at the University of Nottingham, UK, and one of the project partners. He reasons that cattle vary quite dramatically in the levels of methane from their stomachs, so it would be possible to imagine a dairy herd that produced the same volume of milk while reducing their gaseous discharges.

There are other factors: as every human knows too well, gas output is linked to diet. “It is possible to imagine cutting emissions from cattle by a fifth, using a combination approach in which you would breed from lower-emitting cattle as well as changing their diets”, said Professor Garnsworthy. [Read more →]

January 20, 2014   No Comments

U.S. methane emissions vastly underestimated

U.S. Methane Emissions Vastly Underestimated: Study (via Climate Central)

By Bobby Magill Follow @bobbymagill The federal government has vastly underestimated climate change-fueling methane being emitted in the United States, primarily from the oil and gas and cattle industries, according to a new Harvard University study…

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November 27, 2013   No Comments