United Nations Environment Programme (UNEP)
Global  Environment Outlook-1 - The Web version

Chapter 4: Looking to the Future

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Pressures on Natural Habitats

Global Summary

Overall, the world's natural habitat is projected to be at serious risk. Non-domesticated area is projected to drop from its current 70 per cent to about 65 per cent in 2015 and then to 60 per cent in 2050, mainly due to the increased need for land to grow food. Although this change may seem small, many individual species-rich ecosystems in the tropical and subtropical zones are at serious risk, particularly from conversion to agricultural land. In the 20 countries with highest species diversity (WCMC, 1994), about 25 per cent of the current non-domesticated area will be converted until 2050. A great deal of the remaining non-domesticated area would be situated in mountainous, boreal/subpolar, arid, and semi-arid zones, which are generally less suitable for human settlement. The amount of non-domesticated area per person is expected to decline from the current 1.8 hectares to 1.1 hectares in 2015 and to 0.8 hectares in 2050. (See Figure 4.19.)

Pressure on the remaining non-domesticated area world-wide will on average roughly double in intensity. Of the four pressures considered here, this is largely due to climate change, particularly in the northern temperate and boreal zones, and to a lesser extent due to population growth, particularly in the tropics and subtropics. Moreover, the area used for extensive grazing will increase by almost one third (from about 10 per cent to 12 per cent in 2015 and 13 per cent in 2050), intensifying the pressure on the remaining grassland and savannah area.

The world's centres of origin of the main crop plants are not limited to one specific region. They are important from an agricultural point of view: through the process of domestication, wild plants have become sources of new crop species, and they are an invaluable source of genes needed to improve the world's crops. Therefore, preliminary calculations have been made about future pressures on these centres of origin, based on the map published in Global Biodiversity(WCMC, 1992). It is expected that, compared with about 45 per cent of the total area of these centres being domesticated in 1990, some 60 per cent will be domesticated in 2015 and 65 per cent in 2050. Further, the pressure due to climate change would increase by two thirds.

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