The answer to climate-killing cow farts may come from the sea

This
story
was originally published by Mother Jones and is reproduced
here as part of the Climate
Desk
collaboration.

One day in January 2014, police rushed to a farm in Rasdorf,
Germany, after flames burst from a barn. They soon discovered that
static electricity had caused entrapped methane from the flatulence
and manure of 90 dairy cows to explode.

Headline writers had a field day. But the incident pointed to a
serious problem: Ruminant livestock, mostly cattle, account for 30
percent of all global methane emissions, pumping out 3 gigatons of
the gas every year in their burps, farts, and manure. Methane is an
especially potent greenhouse gas: During its 12-year lifespan after
being released, it traps 84 times as much heat as carbon dioxide,
and its effect on global warming over a century is 34 times that of
CO2. According
to the United Nations
, reducing methane emissions from cows
could be one of the quickest ways to slow climate change.

The United States government has
done little
to curb this potent pollution, which makes up 36
percent of the country’s methane emissions. The Environmental
Protection Agency’s AgStar program trains farmers to turn animal
waste into biofuel using anaerobic digesters, but it is optional
— 8,000 farms could implement it, but only about 250 have done
so.

Ermias Kebreab, an animal science professor at the University of
California–Davis, has spent 15 years studying alternative ways to
reduce livestock effusions. Three years ago, he heard that
researchers at Australia’s James Cook University had mixed
bacteria from cows’ digestive systems with red seaweed and
discovered a drastic decrease in methane production. Their lab
experiment suggested that reformulating a cow’s diet to contain 2
percent seaweed could reduce its methane emissions by 99
percent.

Kebreab tried to replicate those results with actual animals.
His team mixed varying levels of Asparagopsis armata, a type of red
seaweed, into the feed of 12 dairy cows over a two-month period.
The results were shocking: When the cattle’s chow consisted of
just 1 percent seaweed, their methane emissions went down 60
percent. “In all the years that I’ve worked in this area,
I’ve never seen anything that reduced it that much,” Kebreab
says.

These are preliminary results, but they offer exciting
prospects. Seaweed doesn’t require precious freshwater,
fertilizer, or land to grow. It can reverse ocean acidification by
absorbing carbon dioxide. We’d have to grow quite a bit of
seaweed to rely on it for sequestration: One study suggests we
could remove the equivalent of 42 percent of all current global CO2
emissions by covering 4 percent of the world’s oceans in seaweed
farms — but that’s a lot of ocean.

And as a review published by the U.N. Food and Agriculture
Organization notes, if aquaculturists remove rocks or native sea
grasses to plant massive seaweed farms, they could disrupt
ecosystems and even alter coastal currents. But responsible seaweed
cultivation could be a boon to marine habitats, providing nurseries
for fish and snails, argues Paul Dobbins, a senior specialist at
the World Wildlife Fund and former president of a kelp farm in
Maine.

The need to rein in methane emissions is especially urgent in
Cali­fornia, home to 1.8 million dairy cows. A 2016 law requires
the state air resources board to implement a strategy to reduce
these emissions by 40 percent from 2013 levels by 2030. In hopes of
helping farmers meet those goals, Kebreab and his team launched a
larger version of his cow study in March, using 21 steers that he
monitored for six months. So far, the results mirror the first
experiment’s, but a full analysis won’t be ready until
December. Kebreab’s biggest hurdle has been finding enough
seaweed; the variety that’s useful for cows isn’t domestically
available.

Massachusetts-based Australis Aquaculture hopes to
cultivate red Asparagopsis on ropes anchored off the coast of
Vietnam. CEO Josh Goldman is excited about feeding his underwater
crop to cows: “You don’t have to rebuild 10,000 power plants in
the world. You basically create a modest feed additive that has a
big leverage effect.”

WWF’s Dobbins says seaweed farming can be a “triple win”:
a way to grow nutritious food for both cows and people, provide
coastal jobs, and improve the marine environment. “Everything you
do in food production has pluses and minuses relative to the
environment,” he says. “Seaweed farming, if done correctly,
actually comes out more on the plus side.”

This story was originally published by Grist with the headline
The answer to climate-killing cow farts may come from the sea

on Nov 3, 2019.

Source: FS – All – Science – News
The answer to climate-killing cow farts may come from the sea