"World Summit on Sustainable Development, Johannesburg, 2002" quoted as "Rio +10" has outlined many options for action. But in the first instance, six areas of concern are of prime importance. Together with climate change, freshwater, deforestation, poverty and biodiversity, world population growth is cited as a determinant element.
Awareness of the role of humans as powerful agents of environmental change is not new. Historically, human action has often been blamed for adverse environmental effects. The first study of population-environment linkages is associated in most people's minds with the work of Thomas Malthus in 1798 which showed concern that population increases in England would quickly outstrip the available food supplies, leading to famine and misery. His argument was based on the idea that while population can grow geometrically, food production cannot because it is limited by the land available. He doubted whether science and technology could enhance life since any gains made through technology would be quickly offset by population increases with eventual disastrous consequences. .
With an alarming ever-increasing rate the world population continues to grow. As a result, more and more pressure is being placed on our land, water, and energy resources to provide us with a supply of food while maintaining the soundness of our ecosystem. According to the United Nations, around one quarter of the human population is malnourished resulting from a combination of insufficient food, low incomes, and inadequate distribution of food. Never has this been ever recorded in history. The general trend indicated by the population growth curve shows that the world population is projected to swell from roughly 6 billion now to some 9 billion in 50 years time. As the world population expands, the food crisis will become increasingly severe, conceivably with the numbers of malnourished escalating the billions.