But no one knows for sure. What is becoming clear, however, is that the greatest threats to the integrity of our oceans come from land-based activities. Humankind is in the process of annihilating coastal and ocean ecosystems and the wealth of biodiveristy they harbour. Worse, the damage is a result of ignorance and inertia as much as outright destructive greed and short-sightedness. At the root of the problem, of course, is burgeoning human numbers and their ever-growing needs.
Population distribution is increasingly skewed.
Recent studies have shown that the overwhelming bulk of humanity is concentrated along or near coasts on just 10 per cent of the earth's land area. Take the example of China, the world's most populous nation. Of China's 1.2 billion people, close to 60 per cent live in 12 coastal provinces, along the Yangtze River valley, and in two coastal municipalities, Shanghai and Tianjin. Along China's 18,000 kilometres of continental coastline, population densities average between 110 and 1600 per square kilometer. In some coastal cities, such as Shanghai, China's largest with 17 million inhabitants, population densities average over 2,000 per square kilometre.