Agricultura, pesticidas e efeito de estufa

"Researchers based at Stanford University in the US recently calculated that the widespread use of mechanisation and artificial fertilisers between 1961 and 2005 avoided the emissions of 161 billion tonnes of carbon that would otherwise have been released through land-use change. (Yes, this is a net figure: carbon dioxide exhaust from all the tractors has been subtracted, as have agricultural nitrous oxide and methane emissions.) In other words, had farms been run organically during this period, huge areas of forest and savannah would have been brought into production to keep people from starving, destroying and releasing the stocks of carbon stored in trees and soils. During the 1961—2005 period global cropland area did increase by 27% — but total yield rose 135%, a jump in productivity that spared vast areas of natural land from the curse of the plough. The amount of additional land that would have been needed to produce this quantity of food at 1961 levels of yields and inputs is truly vast: 1,761 million hectares, an area larger than Russia."
Mark Lynas, in The God Species