It does not take an expert to realise that humanity cannot continue its profligate use of natural resources. The evidence is all around us. Seas are depleted, hundreds of animals are on the brink of extinction and forests which take thousands of years to grow are felled in a week. In its 1998 State of the World report, the Worldwatch Institute warns, not for the first time, that we are reaching the limit of the Earth's capacity to meet our needs. Quoting staggering statistics to show that the growth of the global economy was faster in the past seven years than in the period between the beginning of agriculture and the 1950s, the Washington-based organisation suggests that there is still a chance to change our ways and yet continue to prosper. Many of the policies they advocate are things which only governments or multinational companies can implement. The message which must get through to the world's population is that we will all be victims if attitudes do not alter, and each of us can make small but radical changes in our own behaviour, to help the Earth recover. If everyone in Hong Kong refused to buy food in polystyrene containers, for example, it would make a discernable difference to the litter in the streets, as well as cutting down on the amount of chemicals that contribute to global warming. The coral reefs of Southeast Asia are destroyed because Hong Kong diners are anxious to display their wealth by eating exotic fish, unconcerned that pristine seas are poisoned for that purpose. Such practices could be stopped tomorrow. And if they are not stopped soon, who can be sure that tomorrow will come?