How Meat Contributes to Global Warming

Andy Potts
Key Concepts

Pound for pound, beef production generates greenhouse gases that contribute more than 13 times as much to global warming as do the gases emitted from producing chicken. For potatoes, the multiplier is 57.
Beef consumption is rising rapidly, both as population increases and as people eat more meat.

Producing the annual beef diet of the average American emits as much greenhouse gas as a car driven more than 1,800 miles.
Most of us are aware that our cars, our coal-generated electric power and even our cement factories adversely affect the environment. Until recently, however, the foods we eat had gotten a pass in the discussion. Yet according to a 2006 report by the United Nations Food and Agriculture Organization (FAO), our diets and, specifically, the meat in them cause more greenhouse gases carbon dioxide (CO2), methane, nitrous oxide, and the like to spew into the atmosphere than either transportation or industry. (Greenhouse gases trap solar energy, thereby warming the earth's surface. Because gases vary in greenhouse potency, every greenhouse gas is usually expressed as an amount of CO2 with the same global-warming potential.)

The FAO report found that current production levels of meat contribute between 14 and 22 percent of the 36 billion tons of "CO2-equivalent" greenhouse gases the world produces every year. It turns out that producing half a pound of hamburger for someone's lunch a patty of meat the size of two decks of cards releases as much greenhouse gas into the atmosphere as driving a 3,000-pound car nearly 10 miles.

In truth, every food we consume, vegetables and fruits included, incurs hidden environmental costs: transportation, refrigeration and fuel for farming, as well as methane emissions from plants and animals, all lead to a buildup of atmospheric greenhouse gases. Take asparagus: in a report prepared for the city of Seattle, Daniel J. Morgan of the University of Washington and his co-workers found that growing just half a pound of the vegetable in Peru emits greenhouse gases equivalent to 1.2 ounces of CO2 as a result of applying insecticide and fertilizer, pumping water and running heavy, gas-guzzling farm equipment. To refrigerate and transport the vegetable to an American dinner table generates another two ounces of CO2-equivalent greenhouse gases, for a total CO2 equivalent of 3.2 ounces.

But that is nothing compared to beef. In 1999 Susan Subak, an ecological economist then at the University of East Anglia in England, found that, depending on the production method, cows emit between 2.5 and 4.7 ounces of methane for each pound of beef they produce. Because methane has roughly 23 times the global-warming potential of CO2, those emissions are the equivalent of releasing between 3.6 and 6.8 pounds of CO2 into the atmosphere for each pound of beef produced.

Raising animals also requires a large amount of feed per unit of body weight. In 2003 Lucas Reijnders of the University of Amsterdam and Sam Soret of Loma Linda University estimated that producing a pound of beef protein for the table requires more than 10 pounds of plant protein with all the emissions of greenhouse gases that grain farming entails. Finally, farms for raising animals produce numerous wastes that give rise to greenhouse gases.

Taking such factors into account, Subak calculated that producing a pound of beef in a feedlot, or concentrated animal feeding operation (CAFO) system, generates the equivalent of 14.8 pounds of CO2 pound for pound, more than 36 times the CO2-equivalent greenhouse gas emitted by producing asparagus. Even other common meats cannot match the impact of beef; I estimate that producing a pound of pork generates the equivalent of 3.8 pounds of CO2; a pound of chicken generates 1.1 pounds of CO2-equivalent greenhouse gases. And the economically efficient CAFO system, though certainly not the cleanest production method in terms of CO2-equivalent greenhouse emissions, is far better than most: the FAO data I noted earlier imply that the world average emissions from producing a pound of beef are several times the CAFO amount.

Solutions?
What can be done? Improving waste management and farming practices would certainly reduce the "carbon footprint" of beef production. Methane-capturing systems, for instance, can put cows' waste to use in generating electricity. But those systems remain too costly to be commercially viable.

Individuals, too, can reduce the effects of food production on planetary climate. To some degree, after all, our diets are a choice. By choosing more wisely, we can make a difference. Eating locally produced food, for instance, can reduce the need for transport though food inefficiently shipped in small batches on trucks from nearby farms can turn out to save surprisingly little in greenhouse emissions. And in the U.S. and the rest of the developed world, people could eat less meat, particularly beef.

The graphics on the following pages quantify the links between beef production and greenhouse gases in sobering detail. The take-home lesson is clear: we ought to give careful thought to diet and its consequences for the planet if we are serious about limiting the emissions of greenhouse gases.

Note: This article was originally printed with the title, "The Greenhouse Hamburger".




http://www.sciam.com/article.cfm?id=the-greenhouse-hamburger

歐洲議會支持減少生產肉食，降低溫室氣體

http://suprememastertelevision.com/tw/bbs/board.php?bo_table=sos_tw&wr_id=709&goto_url=&sca=sos_3&sst=&sod=&url=link2_0&#v

歐洲議會（European Parliament）氣候委員會，日前會商溫室氣體（greenhouse gas）減排目標時，正式承認牲畜會造成全球暖化（global warming），並建議複審畜牧業補助金發放，減少排放甲烷（methane）。

揚斯．荷姆：「你所能做的最有影響力的事，就是減少肉食，或完全停止吃肉，你能夠讓作物有剩餘，用來餵飽今日飢餓的人。」

揚斯．荷姆：「我希望未來的孩童所住的世界，能與自然和諧一致，與動物和諧相處，我們不繁殖動物，不運送動物，當然也不殺害動物。」

讚頌並感謝歐洲議會，和所有相關人士，致力讓肉品的成本如實反應在市場上，並鼓勵食用健康的植物性食品，拯救地球。清海無上師接受詹姆士‧賓恩（James Bean）主持的「靈性覺醒」（Spiritual Awakening）電台節目專訪時詳述，飲食不含動物成分，對遏止氣候變遷（climate change）的助益。

清海無上師：「為了救自己，我們一定要吃素，素食是非暴力的最高表現，也是把愛付諸行動，你認為是嗎？」

詹姆士賓恩：「是，如果你愛動物，為何要吃他們？」

清海無上師：「對，而且素食能遏止80%的全球暖化，終止殘酷，從餐盤做起，為世界帶來慈愛的能量，不再有缺水和水汙染，不再有糧荒、飢荒、戰爭與致命的疾病，省下很多稅金和醫療費用，讓世界更好，有更多有用的新發明，幫助好的組織。」
http://www.jensholm.se/2008/12/02/climate-committee-reduce-meat-consumption
http://www.nutritionecology.org/news/personalities.html
http://www.nutritionecology.org/news/stop_subsidies.html
http://www.jensholm.se/2008/12/02/minskad-kottkonsumtion-i-klimatresolution