The six natural resources most drained by our 7 billion people For how long can we realistically expect to have oil? And which dwindling element is essential to plant growth? static.guim.co.uk/sys-images/Guardian/About/General/2011/10/31/1320058545746/A-woman-collects-water-fr-007.jpg A woman collects freshwater from a public well in San Cayetano, west Nicuragua. Photograph: Oswaldo Rivas/Reuters http://www.guardian.co.uk/environment/blog/2011/oct/31/six-natural-resources-population?newsfeed=true