THEGREENGROK

Cows Let Go a Sigh of Relief


by Bill Chameides | October 29th, 2009
posted by Erica Rowell (Editor)

Permalink | 4 comments

While not comprehensive action, Congress moved on climate this week.

Congress acted on climate this week. And it’s certainly a move to chew over.

Climate change is a contentious issue here in the U.S.A. But the topics of debate are not just about whether there is a scientific consensus or whether a cap and trade is better than a carbon tax. A new favorite is whether Congress will pass a climate bill this year. I’ve heard heated arguments over whether the odds are 1 in 3 or 1 in 4.

As it turns out, amid the raging debate over the odds of passing climate legislation soon, President Obama’s U.S. tour touting the advantages of green energy, and media coverage of the climate hearings in the Senate Committee on Environment and Public Works, both houses of Congress, while no one was looking, acted swiftly on climate this week.

Well, admittedly, it was not comprehensive legislation — Congress did not establish a cap-and-trade system or impose a carbon tax or a border tariff and there were no emission targets for 2020 or 2050. In fact, there were no new regulations or limits imposed on greenhouse emissions. Quite the opposite — Congress, if you’ll excuse the expression, gave a pass to a certain type of greenhouse gas emission: specifically burps and farts from cows and other livestock.

Something to Ruminate On

As I’m sure you know, it is the sad misfortune of cows and other livestock to digest their food through a process known as enteric fermentation [pdf]. A byproduct of the fermentation is methane, which cows vent in burps and farts. It is also their sad misfortune that methane is a powerful greenhouse gas, some 20 times more potent than carbon dioxide (CO2) as a global warmer. So the poor four-legged creatures through no fault of their own contribute to global warming.

And there are a whole lot of global warming big guys and gals hanging out chewing their cud on American farms and ranches. According to the U.S. Department of Agriculture, the United States is home to almost 95 million head of cattle; that’s about one head for every three people. (No need to be worried about cattle taking over the country, however, as we have a very effective population control system that slaughters about one third of the herd or 30 million head each year.)

It’s a Gas, Gas, Gas — but Not a Terribly Lot of It

The Environmental Protection Agency estimates that the emissions from the enteric fermentation produced by our 95 million head of cattle and other livestock total about 140 million tons of equivalent carbon dioxide. Cows produce about 95 percent of that, and while that’s a lot of CO2, it’s not an overwhelming amount. Total U.S. greenhouse gas emissions are estimated at about 7,000 million tons of CO2 equivalents, so enteric fermentation accounts for only two percent of our total emissions.

And yet, despite this drop in the bucket, I am told that cows and their livestock brethren are worried. You see, the U.S. EPA — having been instructed by the Supreme Court to regulate greenhouse gases under the Clean Air Act and having found greenhouse gases to pose a threat to human health and welfare — is now in the process of finalizing its endangerment finding, a step that will likely spur the agency to develop rules and regulations for greenhouse gas emissions.

Is it possible that EPA would look upon those 140 million tons from cows and other livestock as “low-hanging fruit,“ an easier, less lobbied-up target for regulation than, say, power plants? And if so, who is going to speak up for the rights of cows, sheep, and bison to pass their gas across the country’s amber grains and fruited plains?

A Herd Mentality Speeds to Action in the Passing Lane?

The cows’ worries are over. I have recently learned that the livestock of America have formed their own grassroots group known by those in the know as Cows United and Determined (CUD). And CUD has steered EPA in a different direction. No doubt in an attempt to avoid a stampede of protest from CUD, EPA administrator Lisa Jackson stated that the agency had no intention of regulating emissions from ruminants. But Congress (possibly at the urging of their rancher-lobbyist pals as well as CUD) was not taking any chances. This week both houses passed an amendment to EPA’s 2010 appropriations bill forbidding the agency from using the Clean Air Act to regulate cow and livestock emissions.

I am sure you will agree that it is really great to know that when a serious climate issue arises, our congressional representatives are able to act quickly and resolutely. But now here’s my question. Does this mean that anyone who took the odds and bet that Congress would pass climate legislation can now collect their winnings?

filed under: animals, climate change, faculty, global warming, methane
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4 Comments

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  1. Jim
    Oct 30, 2009

    Even though we still need to be concerned about methane, it is my understanding that the methane does not stay in the atmosphere very long when compared to CO2, a few years as compared to a few centuries. Is that correct? Maybe we should just capture that methane and put it to good use, though it could be a little uncomfortable for the cows…

    • Hank Roberts
      Nov 20, 2009

      Jim, Dr. C. ought to respond to your points there with something like 1) methane is a much stronger greenhouse gas than CO2 (it catches heat something like 20x as effectively). 2) methane eventually oxidizes — CH4 plus oxygen becomes CO2 and H2O, both greenhouse gases. I don’t know how much methane reaches the stratosphere before it oxidizes; is it a contributor to moisture in the stratosphere, Dr. C?

      • Bill Chameides
        Nov 24, 2009

        Hank, It is estimated that between 5 and 10% of the methane emitted into the atmosphere gets into the stratosphere. And yes, you are correct, the oxidation of methane on the stratosphere is a significant source of stratospheric water.

    • Bill Chameides
      Nov 24, 2009

      Yes, methane does not stay in the atmosphere as long as CO2 and in that sense has less of a long term impact. The global warming potential of methane, ~20 times larger than CO2, is based on a 100-year average and takes methane’s shorter lifetime into account. Capturing methane from the atmosphere would be great but at a concentration of little more than 1.8 parts-per-million is no easy task.

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