Graphics care of the Livestock Global Alliance, 2016.
Now this is a funny headline: ‘Cow farts can now be regulated in California.’
But it’s also a tad misleading. These news stories really ought to emphasize cow belches.
Belches are the big global warming problem! Cow farts are secondary.
‘Okay, let’s explain. Over the past few weeks, California has been passing a slew of ambitious global warming policies. That included SB 32, which mandates a 40 percent cut in overall greenhouse gases below 1990 levels by 2030. (That’s, uh, pretty drastic!) . . .
‘So that’s where the cows come in. Methane is a particularly potent greenhouse gas, some 34 times as effective as carbon dioxide at trapping heat over a 100-year period. Methane accounts for 11 percent of total US climate pollution. And it comes from a bunch of different sources, including natural gas leaks, landfills, and livestock—the last through decomposing manure and a process called “enteric fermentation.”
‘Oh yes, “enteric fermentation.” Basically, cows evolved to eat grass. Grass is tough to digest (just try it), so cows have specialized four-chamber stomachs that process the food, regurgitate it back up into cud, and then re-digest it. Those stomachs also have various microbes, which break down the food and release CH4, or methane. Most of it comes through burping, a bit through farting.
‘It all adds up. California has a lot of dairy cows, and all that belching and farting and decomposing poop accounts for 5 percent of the state’s total greenhouse gas output. If you want radical emissions cuts, you gotta go for the belches.
‘The good news is that there actually are ways to reduce methane. Altering cow diets is the most promising technique at the moment. In some studies, researchers have fed cows things like infused flaxseed and reduced methane emissions up to 30 percent. The catch is that milk production can go down with some of these diets, and it’s not clear that the reductions are always permanent — the stomach microbes may eventually readjust. So more tinkering is needed.
‘Alternatively, some companies try to capture the methane, . . . . Cargill is putting cow poop in giant domed lagoons to trap the biogas and use it for energy. Argentina, meanwhile, is experimenting with cow backpacks that capture the methane. . . .
‘Better breeding might help, too. Scientists have noticed that different cows can emit wildly varying amounts of methane—by a factor of two or three. If this is influenced by genetics, it might be possible to select and breed only low-emitting cows. Still, figuring out the interplay between genetics, microbiology, and diet is tough, and there’s still a lot for researchers to untangle. . . .
‘Regulation will go into effect no later than 2018, with the aim of cutting methane pollution 40 percent by 2030.
‘There’s no guarantee any of this will be easy. Even simple tasks like measuring methane from hundreds of thousands of cows can be tricky. And, because livestock management can differ from place to place, a diet that works on one farm may not work as well on another. . . So there’s a lot to hash out. . . .
Read the whole article by Brad Plumer at Vox: California wants to regulate cow belches; it’s less weird than it sounds, 2 Oct 2016.
Read more on this topic
Could less gassy livestock be a cash cow? Bloomberg, 18 Aug 2016.
Kenyan cattle found to have much smaller faecal carbon footprints than those used in climate change inventories, ILRI News blog, 17 Jun 2016.
Livestock can significantly reduce greenhouse gases AND deliver benefits to the poor–Nature Climate Change, ILRI News blog, 23 Mar 2016.
As livestock eat, so they emit: Highly variable diets drive highly variable climate change ‘hoofprints’–BIG new study, ILRI News blog, 17 Dec 2013.
Get more climate change information from Vox
Global warming explained, 25 May 2015
7 charts that show why UN climate talks keep breaking down, 22 Sep 2014