Our school is considering a "meatless day" campuswide this spring, to increase awareness of the environmental damage caused by livestock around the globe. The food service that operates our school cafeteria has agreed to facilitate our meatless day. My husband Ken, a biology teacher, has written this summary for students and faculty, to explain the impact of livestock on the world environment:Eating meat is an inefficient use of our diminishing natural resources: land, water, and clean air. We could feed the human population with much less agricultural land if we ate the grains that we presently feed our livestock. For example, it takes 7 lbs of grain to produce a 1 lb weight gain in a steer. A hog needs more than 3 lbs of grain for a 1 lb weight gain. For poultry and herbivorous species of farmed fish, 2 lbs of feed is needed for a 1 lb weight gain (Brown, 2008). Stated another way, we consume fewer natural resources when we ourselves eat the plant-based foods that we feed livestock, rather than running them through animal bodies first.
A closer look at our soybean harvest, as an example, illuminates how this inefficiency makes switching to a vegetarian lifestyle a wise choice. In 2007, the world grew 222 million tons of soybeans, only 20 million of which was consumed directly as tofu, soy milk, veggie burgers, etc. Thirty-seven million tons were used in making soybean oil; the remaining 165 million tons were fed to cattle, pigs, chicken, and fish (Brown, 2008). Averaging the inefficiencies mentioned in the previous paragraph gives roughly 4 pounds of feed needed to produce 1 pounds of meat, a ratio of four to one. This means that the 165 million tons of soybeans we feed to livestock yields only 41 million tons of meat. If we replace this 41 million tons of meat in our diet with 41 million tons of soybean products (eating them directly rather than feeding them to livestock), that would make the remaining 124 million tons of soybeans we grow unnecessary. The same argument can be made for other crops we feed to livestock as well – most of the corn and oats we grow are fed to livestock rather than eaten directly by humans. As shown below, every acre of land not used for farming in the world would act in many ways to improve the health of our planet.
Right now 70% of the agricultural land on earth (and 30% of the earth’s land surface) is set aside for livestock pastures or growing food for livestock (Steinfeld et al., 2006). Every acre that we free up and return to its natural state would reduce our demand for water, expand forests and other natural habitats, and lower the volume of pesticides, herbicides, and antibiotics we release into the environment.
Pasture that was once forest (photo courtesy of www.biology.duke.edu)Since much of the feed we grow for livestock is irrigated, raising livestock consumes an enormous amount of water. Worldwide, the livestock sector accounts for 8% of water used for human activities. Raising one steer, for example, requires 1.2 million gallons of water, considering the irrigation of the steer’s feedcrops. Producing one pound of ground beef requires 5214 gallons, while one pound of either lettuce, potatoes, tomatoes, or wheat, requires only 23 to 25 gallons (Robbins and Ornish, 2001)
As an example of how the livestock industry impacts habitat destruction and deforestation, consider our loss of tropical rain forests. Thus far, roughly 20% of the Amazon rainforest has been cleared either for cattle ranching or soybean farming (soybeans primarily for livestock feed). Tropical rain forests have been estimated to contain from one-third to one-half of the world’s species. As these forests are cut, our global biodiversity will plummet.
In contrast, livestock are so numerous that they account already for 20% of the total mass of all land animals on earth. They preempt 30% of the earth’s land surface from occupation by wildlife. Besides driving deforestation, the livestock industry is one of the main factors behind land degradation, overfishing, sedimentation of coastal areas, and facilitation of invasions by alien species (Steinfeld et al., 2006).
What about the atmosphere and climate change? The livestock sector is responsible for 18% of global greenhouse-gas production. It has a larger impact on climate change than transportation, making eating less meat just as important, if not more so, than buying a hybrid vehicle, switching to fluorescent lights, or buying Energy Star appliances, etc. The livestock industry accounts for 9% of our CO2 emissions, 37% of methane, and 65% of nitrous oxide (all are greenhouse gases). The latter two are more important than many people realize. Methane has 23 times the global warming potential as CO2, molecule per molecule, while nitrous oxide has 296 times.
Livestock is also responsible for 64% of our ammonia production, which contributes significantly to acid rain and acidification of ecosystems (Steinfeld et al., 2006). The loss of trees due to acid rain reduces the earth's ability to absorb CO2 through photosynthesis, and impacts climate directly by altering weather patterns. A tropical forest cools the air around it while cropland heats it; forest loss affects climate around the world.
The livestock industry is also a major water polluter. Livestock produce 291 billion pounds of manure per year in the US – six times the amount of human sewage (1 steer produces 50-60 lbs of manure a day, one dairy cow 120 lbs (Robbins and Ornish, 2001)). None of this waste is sent to a treatment plant; instead it’s sprayed over cropland or housed in lagoons that leak. This waste matter ultimately works its way into our water supply. Nitrate concentrations under hog-waste lagoons have been measured at 10 times safe levels set by the EPA (Kneidel and Kneidel, 2005).
On a factory farm, hog waste pours from automated hog sheds into a "waste lagoon"Our environment is also becoming polluted with antibiotics as a result of their use in the livestock industry. Every year, approximately 25 million pounds of antibiotics and related drugs are administered to animals in sub-therapeutic purposes, primarily for the purpose of boosting growth rates. This is more than eight times the amount used to treat disease in humans (Union of Concerned Scientists, 2003). Livestock typically shed in their feces up to 90% of the antibiotics fed to them, leading to antibiotic resistance in soil bacteria. Research has shown that using manure to fertilize soils also leads to the incorporation of unaltered antibiotics into plant matter, and therefore into our diet (Kumar et al., 2005).
Americans lead the way by far in per capita meat consumption. The average American eats 246 pounds of meat per year (74.4 billion pounds for 300 million people); other industrialized nations eat an average of 176 pounds per person per year; 66 pounds pp per year in developing nations (Nierenberg, 2005). Unfortunately the amount of meat being eaten across the globe is increasing. World meat consumption has more than doubled between 1950 and 2005. Consumption of milk and eggs has also risen. In every country where incomes have risen, meat consumption has too (Brown, 2008).
With our population projected to increase from 6.6 billion to 9.2 billion by 2050, it’s clear that we just can’t go on eating as much meat as we’re eating today. Change is easy. One day at a time. We can all start with one meatless day per week.
Photo courtesy of www.nytimes.comSources:
Brown, L.R. Plan B 3.0: Mobilizing to Save Civilization.
Kumar, K., S.C. Gupta, S.K. Baidoo, Y. Chander, and C.J. Rosen. 2005. “Antibiotic uptake by plants from soil fertilized with animal manure”. Journal of Environmental Quality, 2005, 34:2082-2085.
Nierenberg, D. “Worldwatch Paper #171: Happier Meals: Rethinking the Global Meat Industry.” Worldwatch Institute, 2005. http://www.wellfedworld.org/PDF/WorldWatch%20Happier%20Meals.pdf
Robbins, J., and D. Ornish. The Food Revolution: How Your Diet Can Help Save Your Life and the World.
Union of Concerned Scientists. “Food and Environment: Antibiotic Resistance”. October 2003.
Keywords:: campus meatless day environmental impact of meat
No comments:
Post a Comment