Saturday, February 21, 2009

Grass-Fed Cattle Have A Bigger Carbon Footprint Than Grain-Fed Cattle

Mark Bittman from the New York Times opened a can of worms with this little blog post this week:
"A report from Science News (via Food Times) argues that beef produces 19 kilograms of CO2 for every kilogram served; that grass-fed beef is worse — yes, worse — for global warming than feed-lot beef; and that for every percentage reduction we make in meat consumption we’ll see a corresponding reduction in its contribution to global warming."
- Mark Bittman, Meat and Global Warming
From that Science News article he linked:
"[Green house gas emissions are] roughly on the order of 50 percent higher in grass-finished systems."

"The reason: "It's related to the much higher volumes of feed throughput and associated methane and nitrous-oxide emissions." He added that most pastures were highly managed, and subject to "periodic renovations and also fertilization." Finally, with grass-fed cattle "there is also a high [grass] trampling rate. So the actual land area that you need to maintain magnifies that difference."
- The Carbon Footprints Of Raising Livestock For Food, Science News, Feb 15
I learn something every day.
Photo of grass-fed calves from Janzen Family Farms.


Matt said...

While this may be true in the scientists' bubble, the reality is that a well-managed system actually adds organic matter back into the pasture land. Well-managed systems do not use off-farm inputs like fertilizer. In fact, well-managed systems use their animals' natural fertilizer in the process of farming(and these operations raise more than just cows). This, in effect, combats global warming.

The best and most famous example is Joel Salatin's Polyface farm (famous because of Michael Pollan). He calls himself a grass farmer because he rotates his animals in a way that grows grass. I saw him speak a few years ago and he explained he added something like two percent organic matter back into his soil in the past couple decades.

I'm not sure where he gets this fact, but he says if all pasture lands in the US added just one percentage point of organic matter in 10 years, we could sequester all of the carbon that we emitted since the beginning of the Industrial Age.

RB said...

Matt beat me to the point I was going to make. I agree that grass fed beef the way Polyface Farms raises its does not have the same impact on the environment as grass fed beef using conventional industrial practices. The study probable just looked at industrial farming.

Here's some links to true pastured raise grass fed beef:

Polyface Farms:
Eat Wild - List of grass farms throughout America
Grass farming Benefits the Environment

Alex Avery, Hudson Institute said...

Sorry guys, but Joel Salatin (a neighbor of mine) is notoriously wrong on such facts.

Pasture's are mostly at equilibrium for carbon, especially in our (Salatin's) clay soils of the Shenandoah Valley.

No matter how you slice it, the far larger (roughly 2X) methane emissions from the diet of grass (cellulose) compared to corn (starch) of grass-fed cattle swamps the additional CO2 from growing the corn feed (N fertilizer production, pesticides, feed transport). Methane is 23X as powerful a GHG according to the UN IPCC as CO2. That's the difference.

If you want to argue land for carbon sequestration, then the fact that finishing cattle on grain takes only 1/3 as much land per pound as organic grass-fed beef surely counts for something. The Searchinger paper in Science says 10,000+ lbs of CO2 per year for 30 years, which means that even if the CO2-equivalent GHG emissions per pound of beef were equal between grass-fed and corn-fed beef, the additional land required by the grass-fed system would add up to a 60% larger CO2-equivalant GHG emissions per pound for the grass-fed system.

Admit it, on GHG emissions, grass-fed loses. It's biological reality of rumen bacteria when digesting grass to make vastly more methane.

Find another justification of your beef, or just say it doesn't matter and say you like it better.

Bix said...

I don't see how, from what I've learned, grass-fed cattle don't produce more green house gases than grain-fed cattle. Not that it justifies the current system of grain-fed, just that its impact on global warming needs to be addressed.

Eating "grass-fed" doesn't take the solution of eating less meat off the table.

In fact, I'm beginning to think that (as RB said) what is sold as "grass-fed" meat isn't coming from the iconic cow-in-the-pasture, at least not all the time. I think it's just another tactic to appeal to a possibly more informed? market.

Didn't we see that with "Certified Humane" chickens ... whose beaks were still cut off to accommodate crowding tens of thousands of them into one room.

Jimmie said...

I raise cattle, and I raise them on grass and provide them with grass and alfalfa hay in the winter. So, I tend to scoff at reports that cattle are primary contributors to Global Warming. But it has become such a part of mainstream 'belief' that I finally had to try and understand how it is that a cow causes global warming.

There is a lot of chatter right now about grassfed beef production being worse for the environment than grainfed. Not so.

While a grassfed animal does produce more methane via their belching, the grain fed animal produces manure that contains more Nitrous Oxide, almost 300 times, or ~93%, more toxic to the ozone than methane. Not to mention the Carbon Dioxide emissions that result from the cropping of the feed grains, and the nitrous oxide from the fertilizers used to crop the grain.

The FAO's 2006 report that damned the livestock industry actually provides NO estimation of the net carbon effect of converting to an all grain livestock industry. None. And certainly no estimation of the impact on water supplies from cropland fertilizer runoff.

Apparently they'd rather spend their time coming up with some vaccine, or chemical additive for the cow to eat, to reduce their belches.

Anonymous said...

even IF grass-fed animals emit more gas, if we switch to organic agriculture practices and HEAL the soil - the soil itself will HOLD and contain plenty of the carbons that would otherwise be in the atmosphere. (Read MARIA RODALE'S book: ORGANIC MANIFESTO.) Heal the soil and remove the carbon 'problem'.

Dave said...

Double standards anyone?

So in the rest of our industrial society, anything that uses carbon in a circular cycle is "carbon neutral". This was highly touted when talking about 'bio-fuels' and ethanol. While at the same time it is ignored in agriculture, even though it is a much more direct cycle, the grass pulls carbon directly from the air and the cow eats it. SOME of that carbon is then out-gassed back as methane, which oxidizes fairly quickly into CO2 and water. Then of course we eat the rest and a most of that is returned to the environment as well.

Furthermore corn or grain fed beef looks MUCH worse because of all the fossil fuels that go into traditional farming for the grain. Typically about 10 calories of fossil fuel are used to produce 1 calorie of food.

Anonymous said...

Why are people trying to justify eating meat?? It's as silly as justifying smoking "low-nicotine" cigarettes, when SMOKING is the problem. Eat a plant-based diet and be done with excuses.