Genghis Khan the GREEN: Invader killed so many people that carbon levels plummeted

New legacy: Genghis Khan's bloody conquests scrubbed 700million tons of carbon from the atmosphere as depopulated land returned to forest Genghis Khan has been branded the greenest invader in history - after his murderous conquests killed so many people that huge swathes of cultivated land returned to forest.The Mongol leader, who established a vast empire between the 13th and 14th centuries,