A Global Diet on Livestock Emissions

by Bill Chameides | November 10th, 2009
posted by Erica Rowell (Editor)

Permalink | 5 comments

In the search for low-hanging fruit in climate mitigation strategies, are emissions reductions from livestock rearing being considered?

You’ve heard about REDD, the program to “reduce emissions from deforestation and degradation.” Why not RECC, an effort to Reduce Emissions from Cows and Cattle?

Globally, we emit greenhouse gases (GHG) at a rate equivalent to about 40 billion tons of carbon dioxide (CO2) per year. (Sources here and here.)

About 77 percent of the total emissions are in the form of carbon dioxide, but other gases are important. Emissions of methane (CH4) account for about 15 percent of the total, and nitrous oxide (N2O) emissions make up another eight percent of the GHG pie. (See graph below.)

Overhauling Energy Sources Must Play Big Role in Tackling Climate Change

The major contributor to CO2 emissions comes from burning fossil fuels — some 57 percent of the 40 billion tons cited above. So climate change mitigation will require a major alteration in the way we produce energy to power our cars, our homes, and our factories. To succeed in slowing and then ultimately reducing global emissions of greenhouse gases will require:

Global Anthropogenic Greenhouse Gas Emissions in 2004. Note: Other CO2 includes cement production and natural gas flaring. (Source IPCC)
  • new low-carbon technologies,
  • a greater reliance on renewable energy, and
  • a greater focus on efficiency.

But revamping the world’s energy infrastructure is no simple task. Here are just three complications:
•    We’ve already made enormous investments in fossil-fuel intensive facilities;
•    Low-carbon replacements are, in many cases, still in the development phase; and
•    Integrating available renewable energy sources such as wind is problematic because of limitations of our electric grid.

And so policy makers have been looking for emissions from so-called low-hanging fruit outside the energy sector — not as a substitute for cutting energy emissions but as a way to jump-start reductions while we tool up to make the more difficult energy-related cuts.

The Low-Hanging Fruit of Trees

One example is emissions from deforestation and forest degradation. According to a recent paper in Nature Geosciences, emissions from the destruction and degradation of tropical rain forests amount to about 12 percent of the total global greenhouse emissions; including emissions from burning peatlands increases that slice of the pie to about 15 percent.

The REDD program, up for consideration at next month’s climate talks in Copenhagen as part of the next global climate agreement, would address these emissions by providing a mechanism for developed economies to offset their emissions by paying the topical rain forest nations to slow their destruction of these unique and valuable ecosystems. Great idea.

But if emissions from deforestation are a good target, why not also take aim at emissions from livestock?

The Low-Hanging Fruit of Cattle

We all know that we raise a lot of animals to feed a world of almost seven billion. But do you know how many? According to a U.N. report, there are about 1.5 billion cattle and buffalo, 1.8 billion small ruminants, almost 1 billion pigs, and a whopping 17.4 billion poultry birds. Think about it — for every person on the earth, that’s about a quarter of a cow or its equivalent, a seventh of a pig, and 2.5 feathered friends.

Given those numbers, it’s not too surprising that livestock turn out to be directly or indirectly responsible for a whole lot of greenhouse gas emissions. Here are some numbers from that same U.N. report.

  • CH4 emissions from enteric fermentation amount to about 2 billion tons of CO2 equivalents per year or about 6 percent of the total global greenhouse gas emissions.
  • N2O emissions mostly from the decay of manure amounts to another 2 billion tons of CO2 equivalents per year.
  • CO2 emissions from the production of the energy needed to support the livestock industry worldwide is small — less than 0.2 billion tons per year.
  • But CO2 emissions from land use change (e.g., destruction of forests and grasslands) to raise cattle are estimated at 2.7 billion tons of CO2 or 8 percent of the total.

All told, estimates by the U.N.’s Food and Agriculture Organization put livestock production and management at about seven billion tons of CO2 equivalents per year — that’s more than 20 percent of the total greenhouse gas emissions.

If we leave out the emissions from land use change change (which is largely contained in the numbers for deforestation and forest degradation), livestock emissions still amount to about 4.6 billion tons per year or 14 percent of the total.

The Low-Hanging Fruit Not Being Considered Ripe for Plucking

Though greenhouse emissions from livestock look to be as large as or even larger than those from deforestation and forest degradation, because they are related to agricultural activities, most animal-production emissions (like those from deforestation and forest degradation) will not be included in a national or international emissions cap.

But unlike deforestation and forest degradation which will have its REDD program, no similar program, like one to Reduce Emissions from Cows and Cattle, appears to be on the horizon.

But why not? There are things farmers can do to cut livestock emissions. (Check out this recent New York Times op-ed.) Here are some examples:

  • Changing the diet of cattle: Some evidence suggests that feeding cattle with grass instead of grains can reduce methane emissions from enteric fermentation. Replacing grain feeds with grass eliminates the emissions related to cultivating and harvesting grains; less fossil fuels to drive the tractors, less N20 emissions from fertilizers, less water for irrigation.
  • Genetic modification: There’s potential for using genetic modification to develop cows that produce less methane.
  • Manure: Better waste management can reduce or eliminate the emissions of nitrous oxide and methane.

A lot of people out there believe humanity needs to get out of the livestock business and go vegan (see here and here). That’s a tall order and unlikely to happen any time soon if ever.

There are less radical calls to just cut down on meat consumption. But with rising economies in the developing world, meat demand is increas
ing rather than decreasing. (See here and here.)

In the meantime, we must begin cutting greenhouse gas emissions, and given the difficulties we face in accomplishing this, we can’t afford to give a free pass to a sector of the global system that’s responsible for 14 percent or more of the total emissions. Not including something like RECC would be rather, ah, reckless.

filed under: animals, carbon dioxide emissions, climate change, deforestation, faculty, forests, fossil fuels, methane, waste
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  1. Ken Towe
    Nov 16, 2009

    Speaking of “free passes”, what about REBP? An effort toward Reducing Emissions from Biodegradable Products by shifting to biodurable or bioresistant materials. Although biodegradable materials are clearly useful from an environmentally aesthetic point of view their more rapid bacterial breakdown places CO2 more quickly back into the atmosphere. If lowering of anthropogenic CO2 is an absolutely certain goal and solution then the manufacturing of biodegradable products is not helping. Indeed, they are part of the problem. The long term burial of carbon compounds should be the goal, not their rapid biochemical recycling.

    • Bill Chameides
      Nov 18, 2009

      Ken: The RE’s have it.

  2. Hank Roberts
    Nov 14, 2009

    I think you need numbers on this. Don’t fall for the “cow tax” story, the claim that the government plans to put a price on cow burps — which appears to have been used to shoot down the EPA’s regulation of the really big problem, the industrial pig farm methane from manure. The stuff’s just beginning to be easy to measure and document —– Reporting of Greenhouse Gas Emissions for Greenhouse Gas Registry: This amendment added language to the bill prohibiting EPA from requiring livestock feedlots to report on their methane emissions as part of the reporting of greenhouse gas emissions for the Greenhouse Gas Registry. (This Latham (R-IA) amendment was adopted by a vote of 31-27.) Biological Sources of Greenhouse Gas Emissions: This amendment added language to the bill prohibiting EPA from promulgating a regulation to require Clean Air Act permits for emissions from biological processes associated with livestock production. (This Tiahrt (R-KS) amendment was adopted by a voice vote.) ———————- The EPA history is here at the link below. EPA responses to some of the bogus stuff: “to clarify: only beef producers that have manure management systems that meet or exceed the threshold limit will be required to report under the rule. The statement that burden is placed on all beef cattle producers is inaccurate.”

    • Bill Chameides
      Nov 18, 2009

      Hank: I guess you didn’t see the tongue in my cheek. And, with regard to a cow tax, see my earlier post ( ). I agree EPA never had any intention of taxing cow burps, but I bet you didn’t know it was as a result of the work of CUD.

      • Hank Roberts
        Nov 20, 2009

        Sorry, call me humorless, but I think people are confused enough as is. Joke: “emissions from livestock” — burps and farts, oh ho ho ho. Fact: Emissions from feedlots. Law: “prohibiting EPA from requiring livestock feedlots to report on their methane emissions” Law: “prohibiting EPA from promulgating a regulation to require Clean Air Act permits for emissions from biological processes associated with livestock production.” Joke: “biological processes” — haha, farts and burps, oh ho ho ho. Fact: pigshit and cowshit, hosed out of concrete-floored barns into lakes where anaerobic organisms break it down, releasing lots of methane. ——- It’s too easy to lose the point by focusing on the tiny source where everyone’s attention has been directed, and lose the point that the big problem has been exempted by two last minute amendments, one by voice vote so we don’t even know who decided to do this. There must be journalists (are there still journalists?) who know what happened there. Doesn’t this really screw up projects that were going to collect methane, quantify it, get greenhouse gas removal credit for it, and burn it as fuel replacing equivalent amounts of fossil fuel? And what happens to those big lakes of ho-ho-ho that could have been documented and regulated starting in December? Years of good scientific work led up to that final regulation being published. I’m sorry, I know it’s funny. But I can’t laugh. My little planet is all alone in the dark, in a silent universe. And we’re making poop jokes about what we’re doing??

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