If you wish to find something to blame mankind for why not regard the plant and animal worlds? Here one can readily prove the extinction of thousands of varieties of each in order to promote the more productive and beneficial! Nevertheless, many others have been obliterated in the name of Hunting (killing for pleasure) and land clearance for mineral recovery or one shot farming. When the last tree is gone and O2 drops below 17% and CO2 hits the 1% mark then the world will be reduced to several billion mexican type people squatting under their sombreros unwilling to move for any reason. The last man standing will then mutate into a cockroach safe in the knowlege that this was indeed the way in which the dinosaurs died out. After a short few million years it will all start over with a new and different type of pillock who will worship a tattered and dishevelled photo of Gordo the unbelievable of jockland and make houses which cost so much that no one can afford them and perhaps a war or two just for a laugh!