Terrible though they are, the mainland's disastrous floods along the raging Yangtze River may well prove the turning point in the Government's list of priorities. A willingness to acknowledge that one of the causes of the devastation being so great is uncontrolled logging in river catchment areas is the first step toward the application of economic policies based on sustainable development. For decades scientists have warned that there was a limit to how long the human race could plunder the earth before suffering the consequences. Now we are being made to understand the message. The cyclical weather pattern known as El Nino has proved a convenient excuse for a great many of the so-called natural disasters which have affected the planet in recent times. But drought, desertification, erosion, cyclones, heat-waves in one hemisphere, arctic winters in another, and abnormal climates in almost all regions of the world are unlikely to be simply the result of fickle nature. Beijing's decision to stop all timber operations in the upper reaches of the Yangtze in Sichuan province is a necessary response to the catastrophe that has claimed thousands of lives, ruined vast tracts of farmland and will cost the country billions of dollars. Logging was an important industry in a densely populated region with high unemployment and vast rural poverty. To stop it now will no doubt inflict more hardship on people who can no longer graze cattle or collect firewood on land where regeneration is underway. But the authorities now have no choice. In a reversal of previous policy, the Government will now plough resources into replanting and conservation. Labourers who worked as loggers will be employed in replanting and tree protection. The mainland is setting an example which other countries should heed. Last week, US Vice-president Al Gore warned that unless pollution was controlled, the damage to the ozone layer would be irreversible. His own country is the major culprit, and it can offer no excuses of third world debt or lack of funds. America, too, should give a lead in conservation before it is too late.