Farming will cause more damage than global warming

"Tilman and nine other ecologists in the U.S. forecast that over the next 50 years growing populations and an increasing demand for meat will mean the world needs new farmland covering an area the size of the U.S. Meeting this demand will probably see the destruction of 'the vast majority of the rainforests and savannah grasslands in Latin America and central Africa, which harbour a large portion of the Earth's biological diversity.'"