There are currently about 20 billion chickens, 1.5 billion cows, over 1 billion sheep and almost a billion pigs in the world. About 35 million square kilometres of land are used for rearing this animals (almost a size of the whole of Africa). The lack of CO2 absorbing trees is the major reason why global levels of CO2 is increasing. If these lands can be properly managed and returned to its natural state of grassland or forests, it will help prevent the global climate issues.