Migration is increasing as a survival strategy for Africa's rural poor, putting great pressures on the environment and natural resources of the new settlement areas and contributing to the growing urbanization problems. In fact, urbanization has become one of the most conspicuous consequences of Africa's agricultural decline. The cycle of soil degradation, followed by expansion of agriculture into new but marginal land, contributes to many other problems as well. It is a major cause of deforestation and contributes to desertification and the loss of biodiversity, for example. It also contributes to global climate change, since diverse populations of soil microorganisms constitute one of the planet's largest sinks for atmospheric carbon.
Poor soils produce small populations of microorganisms, which absorb less carbon.
Also, disturbing soils to develop new agricultural areas results in large fluxes of carbon to the atmosphere. Just halting nutrient loss would require average fertilizer applications in Africa to rise from 10 to 50 kilos per hectare. Nor would they alone solve the problem of reduced food production. Every dollar of international assistance spent on emergency food supplies in the region diverts resources from the building of infrastructure and institutional capacity needed to ensure long-term food security. Extreme poverty, receding in most other parts of the world, is on the rise in Africa.