From Helen Haran, St Albans, Hertfordshire, UK
Andy Coghlan reports that no society manages to live well without overusing natural resources (10 February, p 10). He misses the key that could unlock this conundrum: a reduction in world population, especially in rich countries. This is particularly important at a time when the US administration has cut its funding for family planning in developing countries. Population growth will not slow down unless contraception is made available to all who wish to have it.
