Commentary: Cows singled out again on gas emissions

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Last year, a couple of scientific organizations in Boulder, Colo., made outlandish claims about gas emissions and cows.

They concluded that cows contribute at least as much to the smog problem in Los Angeles, Calif., as automobiles. Read more.

Somehow, I just couldn’t let that one slide. For one thing, the prevailing winds in the Los Angeles area are from west to east, which would carry ammonia and other gases away from the city ― toward the dairy farms that lie to the east. And, the study’s numbers on the amount of ammonia emissions potentially contributed by dairy cows didn’t add up either. 

Now the same organizations ― Cooperative Institute for Research in Environmental Sciences at the University of Colorado and the Earth System Research Laboratory of the National Oceanic and Atmospheric Administration in Boulder ― have teamed up with others on a second study that strains credulity.

It uses some of the same methodology by measuring gas emissions from airplane flights and tall towers. But instead of doing this in a localized area like Los Angeles, they have somehow expanded their view to include the entire United States. And special attention seems to have been focused on the states of Kansas, Oklahoma and Texas. (For an abstract of the study, click here.)

And if it’s Kansas, Oklahoma and Texas, it must be cows and oil/natural gas extraction that’s causing the problem!

Then, the news media picks up on it and starts blaming cows.

A story that really bothered me was carried on the Fox News web site with the headline, “Big methane burp: Cow farts a greater problem than EPA previously thought, study says.” The original headline on Tuesday quoted the EPA as saying this, but the EPA hadn't had time to go through the study yet. At least the headline was changed to quote the study instead of the EPA. And while cow farts may be funny to headline writers, flatulence may be responsible for only a small part of emissions when compared to other possible sources, such as fermenting cattle feed. The story itself did not quote anyone from the livestock industry.

Rather than trying to measure things from airplanes, the researchers need to get down to farm level.

We need good baseline measurements.  

Studies that have been done in the past show a wide range in annual emissions from dairy cows. Three dairy herds in Wisconsin showed ammonia emissions of 41.8 to 44 pounds per cow per year, but other studies have shown numbers on either side of that.  

When the 2012 study came out saying cows were as guilty as cars for LA’s smog, I contacted Ying Wang, director of Life Cycle Assessment research for the Innovation Center for U.S. Dairy. She told me that the EPA had done a study that found the average ammonia emissions per cow per day are approximately 60.9 grams. When you take 60.9 grams and multiply them by the 298,000 cows in the eastern LA basin (as cited by the Boulder researchers), you get 18.15 million grams per day, which is about 18 metric tons. Yet, the Boulder study blamed cows for 33 to 176 metric tons per day. Look even further and there aren’t that many cows. Dairy cows are most obvious presence in the area, and at the time the study was released in the spring of 2012 the Milk Producers Council of California estimated there were about 100,000 mature dairy cows ― milking and dry ― in the area. That would put ammonia emissions closer to 6 metric tons than the 33 to 176 estimated by the Boulder group.

Cows as guilty as cars? I would rather be caught in a closed garage with a group of cows than one running automobile.

 

 

 

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Julie    
Burlington, VT  |  November, 27, 2013 at 03:35 PM

If humans around the world are serious about reining in greenhouse gas emissions, we have to stop pointing fingers. Rather than looking at what sector produces the most emissions, we need to figure out how to systemically reduce emissions. Many sectors are interconnected such that reductions in one sector may be made while increasing emissions in another. Any time one sector reduces it's emissions, the other sectors will produce more when looking at percentages. To make a difference, the total emissions need to be reduced.


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