In a 2006 report, the U.N. Food and Agriculture Organization (FAO) concluded that worldwide livestock farming generates 18% of the planet’s greenhouse gas emissions — by comparison, all the world’s cars, trains, planes and boats account for a combined 13% of greenhouse gas emissions. Much of livestock’s contribution to global warming come from deforestation, as the growing demand for meat results in trees being cut down to make space for pasture or farmland to grow animal feed. Livestock takes up a lot of space — nearly one-third of the earth’s entire landmass. In Latin America, the FAO estimates that some 70% of former forest cover has been converted for grazing. Lost forest cover heats the planet, because trees absorb CO2 while they’re alive — and when they’re burned or cut down, the greenhouse gas is released back into the atmosphere.