Towards a green economy

Little or no water scarcity Physical water scarcity

Approaching physical water scarcity Economic water scarcity

Not estimated

Definitions and indicators

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Little or no water scarcity. Abundant water resources relative to use, with less than 25% of water from rivers withdrawn for human purposes. Physical water scarcity (water resources development is approaching or has exceeded sustainable limits). More than 75% of river flows are withdrawn for agriculture, industry, and domestic purposes (accounting for recycling of return flows). This definition – relating water availability to water demand – implies that dry areas are not necessarily water scarce. Approaching physical water scarcity. More than 60% of river flows are withdrawn. These basins will experience physical water scarcity in the near future. Economic water scarcity (human, institutional, and financial capital limit access to water even though water in nature is available locally to meet human demands). Water resources are abundant relative to water use, with less than 25% of water from rivers withdrawn for human purposes, but malnutrition exists.

Figure 6: Areas of physical and economic water scarcity Source: Molden (2007)

From a government perspective, when water supply and sanitation services are inadequate, large amounts of revenue are spent dealing with the impacts of disease, rather than generating wealth (Tropp 2010).

In recognition of these fundamental and pressing challenges, governments have committed collectively to a set of MDGs, which, among other things, aim to halve the number of people without access to clean water and adequate sanitation services by 2015 (Box 2). By providing access to clean water and adequate sanitation services at an affordable price people can begin to save, invest and take a longer-term view of their future7

. A

transition to greener approaches to resource use and investment becomes possible.

Water scarcity Exploring opportunities to invest in the construction of dams, the International Water Management

7. In this context, Water, Sanitation and Hygiene (WaSH) initiatives, and specially the teaching of basic sanitation and hygiene to communities and school children will also prove critical.

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Institute (IWMI) has identified two types of water scarcity: physical scarcity and economic scarcity (Figure 6). In regions where there is physical scarcity, the sustainable supply limit has been reached and little opportunity to construct more dams remains. In regions where the scarcity is economic, however, it is possible to increase supplies if the financial resources necessary to build a new dam can be found. The International Water Management Institute is of the view that economic scarcity is widespread in sub-Saharan Africa and in parts of South and South-East Asia (Molden 2007).

There is general consensus that when people have access to less than 1,700 cubic meters of water per year, a considerable proportion of them will be trapped in poverty (Falkenmark et al. 1989). Taking a different approach, the Organisation for Economic Cooperation and Development (OECD) defines water stress as “severe” when the ratio of total water use to renewable supply exceeds 40 per cent (OECD 2009). Using this measure, the OECD has estimated that by 2030 nearly half the world’s population (3.9 billion