According to the UN Food and Agriculture Organization, an estimated 18% of the world's man-made greenhouse-gas emissions come from livestock. In the U.S. beef production accounts for the equivalent of the annual emissions of 24 million automobiles.
Michal Pollen, author of The Omnivore’s Dilemma, states that “much of the carbon footprint of beef comes from growing grain to feed the animals, which requires fossil-fuel-based fertilizers, pesticides, transportation.” Raising grain-fed cattle also results in the destruction of millions of acres of grassland and swamps being converted into cropland for grain-fed cattle.
Raising grass-fed cattle is sustainable. The cattle graze across pastures and cut the grass which keeps it growing and they tread manure into the soil and keep carbon dioxide underground.
But is it better for you? Research from California State University shows beef from grass-fed has lower levels of unhealthy fats and higher levels of omega-3 fatty acids.
99% of beef sold in the U.S. comes from grain-fed cattle but you can buy U.S. grass-fed beef at local farms and online.
Abend, Lisa. “How Cows (Grass-Fed Only) Could Save the Planet.” TIME. 25 Jan 2012. Web 11 Oct 2012. <http://www.time.com/time/magazine/article/0,9171,1953692-1,00.html
Parker-Pope, Tara. “Switching to Grass-Fed Beef.” New York Times. 11 Mar 2010. Web 11 Oct 2012. <http://well.blogs.nytimes.com/2010/03/11/switching-to-grass-fed-beef/
“Where to Buy Grass-Fed Beef.” Washington Post. 17 Oct 2007. Web 11 Oct 2012. <http://www.washingtonpost.com/wpdyn/content/article/2007/10/17/AR2007101700808.html
“Global Warming and Pasture-Raised Beef Production in the U.S..” Union of Concerned Scientists. Web 11 Oct 2012. <http://www.ucsusa.org/food_and_agriculture/science_and_impacts/science/global-warming-and-beef-production.html