Monday, August 11, 2008

Major Contributors to Greenhouse Gases- It Isn't Cars

Jack Dini
Livermore, CA

“It’s a silent but deadly source of greenhouse gases that contributes more to global warming than the entire world transportation sector, yet politicians almost never discuss it, and environmental lobbyists and other green activist groups seem unaware of its existence,” reports the Los Angeles Times. “Livestock are a leading source of greenhouse gases. Why isn’t anyone raising a stink.” (1)

In ‘Livestock’s Long Shadow,’ (The Report) released in 2006, the Food and Agriculture Organization (FAO) of the United Nations reported that raising and processing cattle, hogs, poultry and other animals produces 18 percent of greenhouse gases; by comparison 13 percent comes from trucks, cars, and other transportation. And greenhouse gases—those produced directly by animals, and indirectly through the need to transport grain and meat—are only part of the problem. (2)

Carbon dioxide and all the bad things we do with fossil fuels is what we hear about, not that cows and other ruminants, such as sheep and goats, are walking gas factories that take in fodder and besides putting out carbon dioxide also contribute methane and nitrous oxide. The livestock sector generates 65 percent of human-related nitrous oxide , which has 296 times the Global Warming Potential (GWP) of carbon dioxide. Most of this comes from manure. And it accounts for respectively 37 percent of all human-induced methane (23 times as warming as carbon dioxide), which is largely produced by the digestive system of ruminants, and 64 percent of ammonia, which contributes significantly to acid rain. (3)

So what’s a ruminant? Much of the world’s livestock are ruminants—such as sheep, goats, camels, cattle, and buffalo—who have a unique four-chambered stomach. In the primary stomach, called the rumen, bacteria break down food. John Postgate reports, “The rumen is a sort of continuous culture of anaerobic microbes, including protozoa and bacteria, which collectively ferment the starch and cellulose of grass to yield fatty acids, methane and carbon dioxide. Rumen juice is extremely rich in microbes—up to 10 billion organisms/milliliter is commonplace—and they are very active: an ordinary cow produces 150 to 200 liters of gas a day and a large, a well-fed lactating cow is almost a walking gasworks at 500 liters a day. (The gas, by the way emerges from the mouth as a belch, not from the rear end?”(4)

To put this in perspective, on a daily basis, each one of Britain’s 10 million cows pump out the equivalent of up to 4,000 grams of carbon dioxide. This compares with 3,419 grams of carbon dioxide pumped out by a Land Rover Freelander on an average drive of 33 miles. (5)

Livestock now use 30 percent of the earth’s entire land surface, mostly permanent pasture but also including 33 percent of the global arable land used to produce feed for livestock, The Report notes. As forests are cleared to create new pastures, it is a major driver of deforestation, especially in Latin America where, for example, some 70 percent of former forests in the Amazon have been turned over to grazing. (2)

At the same time herds cause wide-scale land degradation, with about 20 percent of pastures considered as degraded through overgrazing, compaction and erosion. This figure is even higher in the drylands where inappropriate policies and inadequate livestock management contribute to advancing desertification.

Yet, as Gelder and Wilcox note in their excellent review of The Report, it also points out that the production of livestock has enormous economic importance. Besides being big business at the industrial level, it is a crucial source of income and a means of survival for vast numbers—nearly a billion—of the world’s poor, for whom it is the only livelihood available. (6)

What To Do?

The Report suggests a number of ways of remedying the situation including programs looking at minimizing land degradation, increasing efficiency of livestock production, improving efficiency of irrigation systems, better ways of treating animal waste, etc. (2)

Researchers are trying to find a diet for cattle to help cut their emissions. One example- giving cows the hormone recombinant bovine somatotropin (rBST), which boosts their milk production, has been discovered to cut their emissions of the potent greenhouse gas methane by 7 percent per liter of milk. Switching a million cows to somatotropin would be equivalent to taking 400,000 family cars off the road. (7)

What can you do as an individual? Become a vegetarian! A University of Chicago study examined the average American diet and found that all the various energy inputs and livestock emissions involved in its production pump an extra 1.5 tons of carbon dioxide into the air over the course of a year, which could be avoided by a vegetarian diet. The researchers found that cutting out meat would do more to reduce greenhouse gas emissions than trading in a gas guzzler for a hybrid car. (8)

On this issue, Tony Wardle of the UK says, “This blows a gaping hole in the government’s global warming rhetoric and the action plans of big environmental organizations—even the Green Party. They have known the facts for years but have been terrified of confronting them for fear of losing support. People don’t mind being told to recycle their bottles, use solar panels, cycle to work or switch to a smaller car—but tell them to go vegan…” (9)

Lastly, in a huge document released in July 2008, the EPA lays out the thousand of carbon controls with which they’d like to shackle the whole economy. Although none of it has the force of law yet, the EPA is alarmed by emissions from domestic livestock. A farm with over 25 cows would exceed the EPA’s proposed limits. (10) So if this does become law, the cost of meat will skyrocket. More reason to become a vegetarian.

1.“Killer Cow Emissions,” Los Angeles Times,, October 15, 2007
2.Henning Steinfeld, et al., “Livestock’s Long Shadow,” Food and Agriculture Organization of the United Nations, Rome, 2006
3.Christopher Matthews, “Livestock a major threat to environment,” FAONewsroom, November 29, 2006
4.John Postgate, Microbes and Man, 4th Edition, (Cambridge University Press, 2003), 133
5.“How to stop cows burping is the new field work on climate change,”, July 10, 2007
6.Austin Gelder and Lauren Wilcox, “The Carbon Hoofprint,” WORLD ARK, May/June 2008, Page 18
7.“Can cow hormone help battle climate change,?” New Scientist Print Edition, July 2, 2008
8.Gidon Eshel and Pamela A. Martin, “Diet, Energy, and Global Warming,” Earth Interactions, 10, 1, 2006
9.Tony Wardle, “Global Warming-Livestock More Damaging Than Vehicles,” November 20, 2006,
10.“The Lawnmower Men,” The Wall Street Journal, July 19-20, 2008, Page A8

1 comment:

Marion Delgado said...

That's (a) world-wide, including (b) lots of places with very few or no cars and (c) expressed in equivalents that (d) only work over a short period of time, because methane has a much greater effect but lasts a tiny fraction as long.

In places with both cars/planes/trains/trucks/boats, etc. and ruminants, the transportation sector has a bigger impact, and for a longer time. Overall, over a longer time period, things like electricity and transport are more important than ruminants - they're about the third issue down.