Demographic dynamics and sustainability is the subject of Chapter 5 of Agenda 21. Demographics is not directly addressed in the Johannesburg Plan of Implementation. The growth of world population and production combined with unsustainable consumption patterns places increasingly severe stress on the life-supporting capacities of the earth. These interactive processes affect the use of land, water, air, energy and other resources. Rapidly growing cities, unless well-managed, face major environmental problems. The increase in both the number and size of cities calls for greater attention to issues of local government and municipal management. The human dimensions are key elements to consider, and they should be adequately taken into consideration in comprehensive policies for sustainable development. Such policies should address the linkages of demographic trends and factors, resource use, appropriate technology dissemination and development.
There is a need to develop strategies to mitigate both the adverse impacts on the environment of human activity and the adverse impact of environmental change on human populations. The world's population passed 6 billion in 2000 and is projected to reach 9 billion by 2050. Sixty percent of the current population already lives in coastal zones, while sixty-five percent of cities with populations above 2.5 million are located along the world's coasts, several of them already at or below the present sea level.
Demographic dynamics and sustainability was discussed at the third and fourth session of the Commission on Sustainable Development and the nineteenth Special Session of the General Assembly. Population projections and studies are done by the UN Population Division