A 2006 UN report entitled Livestock's Long Shadow: Environmental Issues and Options."
found that 18 percent of global warming emissions come from raising cows, chickens, pigs, turkeys and other animals we eat. That's 40 percent more than all the world's cars, SUVs, airplanes, and other modes of fossil-based transportation, which combined account for 13 percent. For further comparison, every house, residential and office building in the world accounts for just 8 percent.
There's a trend in Europe called "Meat Reducers" where, along with recycling and not taking plastic bags, people are eating meat at least one day less a week. Become a "Meat Reducer." It is a simple thing everyone can do to lower their own carbon footprint.