Pressure on people
The scenarios carry important implications for the provision of basic human needs that are related to broader environmental impacts. In the longer term, global climate change can have a strong impact on the local availability of freshwater. Meanwhile, growing populations and increased economic activity, particularly in agriculture, lead to increased demand for freshwater in most scenarios.
Permutations of these pressures determine those areas and populations that face the greatest challenges in meeting needs. Outside North America and Europe, these challenges increase in all scenarios, along with a trend toward more extreme water stress (see charts below). Differences in policy actions, such as reforms in the pricing of water and shifts in subsidies, and technological improvements can have a strong effect on the size of these challenges. The ability to meet these challenges reflects broader social and economic policies.
| Ecosystems impacted by infrastructure expansion 2002 | |
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Human resource demand continues to take an ever-greater toll on biodiversity. Land-use induced impacts are most often associated with existing infrastructure. In a Markets First scenario, biodiversity comes under threat in nearly 72 per cent of the land area by 2032. The situation is particularly critical in Southeast Asia, the Congo Basin and also parts of the Amazon. The pattern is however evident across all continents and terrestrial ecosystems with the exception of tropical and polar deserts. As much as 48 per cent is directly converted to agricultural land, plantations and built-up areas, compared to 22 per cent today, suggesting widespread depletion of biodiversity. Even the Sustainability First scenario suggests continued biodiversity loss across nearly 56 per cent of the land area by 2032. Source: GLOBIO (see technical annex) |
| Change in selected pressures on natural ecosystems 2002-32 | |
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The maps picture the combined effect of habitat loss and decreasing quality. Security First features a large conversion of natural into agricultural land. By 2032, this conversion is in full motion, especially in the Southern Hemisphere. The Markets First scenario sees a strong decrease of the quality of nature in most regions. In some regions agricultural land is taken out of production and presumed to be reconverted into natural area. However, in biodiversity terms this reconverted land is of low quality during the first decades or longer. Policy First and Sustainability First show roughly comparable results in the scenario period. But their trends by 2032 are different, with Sustainability First moving towards a sharp decrease in pressures. Note Source: IMAGE 2.2 (see technical annex) |
| Population living in areas with severe water stress (%) |
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When more than 40 per cent of the renewable water resources of a river basin are being withdrawn for human use the river basin is considered to be under severe water stress. Source: WaterGAP 2.1 (see technical annex) |
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Under the Markets First and Security First scenarios, the number of people living in areas with severe water stress increases in both absolute and relative terms in almost all parts of the world. These increases are partly due to continuing population growth in water-stressed areas and partly due to new areas experiencing severe water stress (namely large parts of Africa, North and Latin America and Europe). The situation is different under the Policy First and Sustainability First scenarios. In most regions the actual area under severe water stress remains more or less constant or even decreases, due to stable or decreasing water withdrawals, particularly for irrigation. This results in little change in the overall proportion of people living in water-stressed areas by 2032. Nevertheless, the absolute number of people living in water-stressed regions increases significantly across the developing world.
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| Population living with hunger (%) |
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A world of Markets First, although by no means equity-oriented, would reduce the percentage of the population living in poverty, and with it hunger. But in some regions, most notably in Africa, this does not counterbalance population growth. Committed action towards achieving social goals could bring hunger levels back into line with global targets in the Millennium Declaration. Source: PoleStar (see technical annex) |
Similarly, the size of demands for food and the ability to meet them in the different scenarios reflects a combination of shifts in supply and demand, which can be influenced by social, environmental and economic policies. In a Markets First world, even with decreases in the percentage of the population facing hunger, the total number affected changes relatively little and even increases in some regions as populations grow (see charts). The targeting of hunger reduction as a key goal under the Policy First or Sustainability First scenarios, and the general emphasis on more balanced development between regions, helps to achieve dramatic reductions in both the percentages and the total numbers of people affected. The sharp increases in most regions in Security First points to the unsustainability of such a scenario in terms of social acceptability.
