Cutting farming's climate impact

The burps and farts of ruminants (cows) are a key source of methane, which is a powerful greenhouse gas, 90 times more potent than CO2 over ten years.  Fortunately, methane decays within 10 years to CO2, so if we could cut its emissions, we could quickly remove a major greenhouse gas from the system.  Of course, giving up meat and going vegan would do the trick, but many are not prepared to change the habits of a lifetime (full disclosure: I am vegan).  So it's good news that a kind of seaweed may do the trick.

From The Australian Broadcasting Corporation (ABC)

A company commercialising a CSIRO-developed, seaweed feed product, which slashes the amount of greenhouse gases cattle burp and fart into the atmosphere, has won a $1 million international prize for its work reshaping the food system.

CSIRO-affiliated company Future Feed said it would use its Food Planet Prize winnings to create an international commercial fund to help First Nations communities generate income from cultivating and selling the seaweed.

According to the science agency, methane emissions from livestock make up around 15 per cent of global greenhouse gas emissions, and one cow produces on average as much gas emission as one car.

The CSIRO says on its website that methane stays in the atmosphere for about nine years, a far shorter period than carbon dioxide.  However, its global warming potential is "86 times higher than carbon dioxide when averaged over 20 years and 28 times higher over 100 years".

Future Feed director and CSIRO scientist Michael Battaglia said that when added to cattle feed, the product, which contains Australian 'super seaweed' Asparagopsis, virtually eliminated methane from the animals' bodily emissions.

"We know that just a handful [of the product] per animal per day, or 0.2 per cent of their diet can virtually eliminate 99.9 per cent of methane," Dr Battaglia said.  He said the potential for the product to reduce the world's greenhouse gas footprint, if commercialised, was massive.  "We think we can tackle the dairy and the feedlot part of that pretty simply, which may be 5 megatons in Australia and globally 500 megatons of emissions," Dr Battaglia said.  

"That's equivalent to taking 100 million cars off the road.  "But in the long run, if we can start to think about ways to deliver this into grass-fed sectors, the impact is 10 to 100 times more than that."

From The  Guardian newspaper

Feeding seaweed to cows is a viable long-term method to reduce the emission of planet-heating gases from their burps and flatulence, scientists have found.

Researchers who put a small amount of seaweed into the feed of cattle over the course of five months found that the new diet caused the bovines to belch out 82% less methane, a potent greenhouse gas, into the atmosphere.

The finding builds on previous research that showed that seaweed could reduce cows’ methane output over a shorter timespan. “We now have sound evidence that seaweed in cattle diet is effective at reducing greenhouse gases and that the efficacy does not diminish over time,” said Ermias Kebreab, director of the World Food Center and an agricultural scientist at University of California, Davis.

Kebreab conducted the research, published in Plos One, with Breanna Roque, a PhD graduate student.

Cows produce methane via microbes in their stomachs as they digest their fibrous food, in a process a little like fermentation. Methane is shorter-lived in the atmosphere than carbon dioxide but is more than 30 times as effective in trapping heat, making it a major greenhouse gas. A type of seaweed called Asparagopsis taxiformis can partially counteract these emissions from cows.

The seaweed Asparagopsis almost eliminates methane gas from cattle if put in their feed.(Supplied: Future Feed)