The animal agriculture industry is one of the biggest producers of atmospheric carbon dioxide.  Tim Koopman of the California Cattlemen's Association discusses the increased efficiency in cattle production since 1951.  However, David Simon, author of Meatonomics, states, "It takes on average, five times as much land to produce animal protein as it does plant protein.  It takes 11 times the fossil fuels and it takes 40 times or more water to produce animal protein than plant protein."