The latest World Development Report calls on leaders meeting in South Africa at the World Summit on Sustainable Development to recognise the scale of the challenge this surge in population will pose. 'In the MENA region, the strains on natural resources, especially water and fragile lands, are probably the greatest compared with other regions,' says Mustapha Nabli, World Bank chief economist for MENA. Water availability per capita is already one of the world's lowest at an average 1,429 cubic metres a year and that is on course to halve over the next 30 years. The problem of scarcity is compounded by inequitable distribution and quality degradation.

The report says MENA faces great pressure on the housing, education and energy resources of its cities as the population expands. It also calls for action to help the region's poor. 'Rich countries can take such a step by opening their markets to developing world exports' says Nicholas Stern, World Bank chief economist and senior vice-president.