‘The furnaces of the world are burning about 2,000,000,000 tons of coal a year. When this is burned, uniting with oxygen, it adds about 7,000,000,000 tons of carbon dioxide to the atmosphere yearly. This tends to make the air a more effective blanket for the earth and to raise its temperature. The effect may be considerable in a few centuries.’ This is a newspaper excerpt from 1912, which warns about the consequences of unchecked growth. Global concern about the survival of future generations and the planet continued to mount until 1987, when the United Nations defined sustainability – "meeting the needs of the present without compromising the ability of future generations to meet their own needs.”