The head of the UN Environmental Programme’s Green Economy Initiative, Pavan Sukhdev, sits down for tea with The Economist to discuss how to assign an economic value to nature. Once a value is assigned to a natural ecosystem (so that it is no longer external to economic calculations), one principle problem the interview identifies is finding money that will support the value assigned to it. Sukhdev accepts that business must be responsible to its share holders. As a result, he believes companies should be rewarded for not polluting, rather than being punished for having polluted; a positive incentive rather than a negative one will make business more eager to protect the environment.