Water

people) will be living under conditions of severe water stress (Figure 7). The reasons for the emergence of this scarcity include:

■ Population increase – by 2030 the world’s population will have increased by 2.4 billion people. All of these people will to demand access to water for basic needs, to supply industrial goods and grow food;

■ Increased living standards – as countries develop and people become wealthier, they tend to consume more water and more water-intensive products such as meat;

■ Over-exploitation – around the world a considerable proportion of aquifers and river systems are over- used. It has been estimated that 15 per cent of India’s total agricultural production is being delivered via groundwater depletion – the situation that occurs when extraction exceeds replenishment (Briscoe and Malik 2006);

■ Water pollution – an increasing number of water supplies are becoming contaminated by pollutants, with the consequence that less water is available for use or it costs much more to make it usable;

■ Ecosystem degradation – over the last 50 years

ecosystems have been degraded faster than ever before (Millennium Ecosystem Assessment 2005). Freshwater ecosystems, which provide critical services such as the purification of water by wetlands or forests are the most threatened and have been among the hardest hit, and;

■ Adverse climate change8 – when combined with

effects of climate change on dryland production systems, the International Food Policy Research Institute estimates that the aggregate effect of climate change is likely to be a significant reduction in total agricultural productivity. The greatest adverse impacts of climate change on people are expected in South Asia. In the next 40 years, child malnutrition is expected to increase by 20 per cent as a direct result of climate change (Nelson et al. 2009).

8. The IPCC Fourth Assessment Report lists 32 examples of major projected impacts of climate change amongst eight regions (covering the whole Earth). Of these: 25 include primary links to hydrological changes; of the other seven, water is implicated in four and two are general; only one refers to main impacts not obviously linked to the hydrological cycle: coral bleaching. The IPCC technical report (2008) underpinning this assessment report concludes unambiguously, inter alia, that: "the relationship between climate change and freshwater resources is of primary concern and interest". So far, "water resource issues have not been adequately addressed in climate change analyses and climate policy formulations"; and, according to many experts, "water and its availability and quality will be the main pressures, and issues, on societies and the environment under climate change". The Scientific Expert Group Report on Climate Change and Sustainable Development (2007) prepared for the 15th Session of the Commission on Sustainable Development came to similar conclusions.

Balancing supply and demand In an attempt to understand the magnitude of this emerging water-scarcity challenge, the 2030 Water Resources Group has projected global demand for water and, under different scenarios, compared it with likely supply. They concluded that if there is no improvement in the efficiency of water use, in 2030 demand for water could outstrip supply by 40 per cent (Figure 8). Clearly, a gap of this magnitude cannot (and will not) be sustained.

Figure 9 offers an alternative perspective on the magnitude of the emerging water-supply challenge. Under a business-as-usual scenario, improvements in water productivity can be expected to close around 20 per cent of the gap between global demand and supply. Increases in supply through the construction of dams and desalination plants, coupled with actions such as increased recycling, can be expected to close the gap by a similar amount. The remaining 60 per cent, however, must come from increased investment in infrastructure and water-policy reforms that improve the efficiency of water use. If the resources are not found to facilitate a significant increase in efficiency and if the water-policy reforms are not implemented, water crises must be expected to emerge. Figure 9 suggests that the average rate of improvement in water productivity and supply enhancement needs to increase at double the rate of improvement achieved in the past decade. Globally, the time for procrastination is past.

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500 1000 1500 2000 2500 3000 3500 4000

0 2005 No 2030 OECD Low 2005 BRIC Medium 2030 2005 RoW Severe Figure 7: Number of people living in water-

stressed areas in 2030 by country type Source: OECD (2009)

2030

Millions of people