Population and Land Degradation

Population Growth

Human population growth has been cited as a leading factor in land degradation and environmental change in general. Global population increased from 5 billion in 1987 to 7 billion in 2009, an average annual growth rate of 1.4%, with Africa and West Asia recording particularly high growth rates (Figure 1). This increase in population, together with the increase in the gap between the rich and the poor, in the relative access to goods, and in income-earning opportunities, has led to increased demand for food and energy, putting pressure on available environmental resources such as freshwater, fisheries, agricultural land, and forests.

Population changes are further influenced by forced and economic migration, which in turn affects settlement patterns, resulting in migrant refugees who are internally displaced. An estimated 25 million people have been forced to migrate as a result of environmental factors, with approximately 200 million threatened by displacement not only from environmental factors but for political and ethnic reasons as well. An estimated 2 billion people depend on dry lands that bear a legacy of land degradation, and 90% of them live in developing countries.

Migration

Rural to urban migration, or urbanization, is an especially prevalent trend in developing countries. An urban increase of 44%, from 28% to 29%, has been noted in northeast and southeast Asia and is predicted to reach 59% by 2025. An estimated 1 billion people reside in informal urban settlements around the world, with no proper housing or basic services, which has contributed significantly to urban and suburban spread and uncontrolled land transformation. High concentrations of the urban population reside along coastal areas, exerting undue pressure on coastal and marine ecosystems. While these direct causes of land degradation are important, it is the formal urban settlements that have been shown to exert greater pressure indirectly on land.

The multifaceted relationship between migration, urbanization, and, in turn, environmental change leads to natural disasters and land and ecosystem degradation, while consequently changing land use and the demand for ecosystem services. For example, the persistent shift from cereal to animal products and the recent move toward biofuels add to the demand for increased farm production, with unfavorable consequences for farmland rather than forestland. Negative impacts of urbanization, such as pollution, have been detrimental to human health. In Africa, it has been argued that children living in sub-Saharan cities in slums are more likely to die from waterborne diseases than are rural children. Ultimately, the population burden on natural resources and sustainability may increase as populations increase.

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