Last year, the world met its Millennium Development Goal of halving the number of people without access to safe drinking water, five years ahead the 2015 deadline. However, 11 percent of the world' population, or 783 million people, still live without access to safe drinking water, 40 percent of them in sub-Saharan Africa.
By 2050, another two billion people will be added to the planet, of which 90 percent will be in developing countries with high water stress. In tandem, the demand for water is expected to increase by 50 percent, according to the World Water Development Report 2006. Not surprisingly, some policy analysts speculate that the future wars will be fought over the blue gold. The water challenge remains acute for the foreseeable future.
In ranking the top five global risks in terms of impact last year, the World Economic placed the water supply and food shortage crises in second and third place respectively. Both risks are closely associated with land degradation, but land degradation is not perceived as a major risk for global sustainability.
In fact, the close link between land and water makes land degradation the hidden face of water scarcity: the health of the land is critical in the search for sustainable solutions to water resource provision and management. And yet, land degradation, also known as desertification in respect to the drylands, remains the greatest policy blind spot in domestic and global responses to water management.
I argue that urgent measures to monitor and curb land degradation, and to restore degraded and degrading land are needed. These measures need to be explicit and integrated into global and domestic water management policies. Crucial too are policies that pre-empt or minimize vulnerability to climate change and strengthen resilience in the long-term.
The term water scarcity as used here refers to the non-availability and/or lack of access to fresh water resources for consumption and to meet other social, economic, and development demands. Consistent with the United Nations Convention to Combat Desertification (UNCCD), the term desertification refers to land degradation in the arid, semi-arid, and dry sub-humid areas of the world. Land degradation refers to the loss of the productivity of the land due to human activity compounded by climatic variability. Therefore, the distinction between desertification and land degradation is purely geographic and not process-based. The end result of both is barren lands or man-made deserts.
The Land-Water Nexus
Three quarters of the Earth is covered with water. Yet, only 2.5 percent is fresh water, and of this, less than 1 percent is available to sustain all terrestrial life and ecosystems. Land is the natural storage for freshwater, but its storage capacity depends on the health of the land. For example, dryland soils are more fragile than tropical soils in part due to the sparse vegetation cover, and the loss of that cover weakens the storage functions of the soil.
Desertification and land degradation processes lead either to a physical or chemical deterioration of the land. The starting point is often the removal of vegetation cover. The degradation of dryland and non-dryland areas is the gradual loss of the biological productivity of the soil, which can translate into a loss of moisture through increased evapotranspi ration, exposure to wind and water erosion, and so on.
Agriculture is also a key driver of land degradation. Globally, 70 percent of freshwater is used by agriculture. Some practices, particularly mono-cropping, unsustainable irrigation, and other inappropriate land use schemes degrade the soil further by altering its chemical balance--for instance, through salt build up or salinization. Moreover, water consumption in agriculture increases with land degradation.
Land degradation is followed by the inability of the soil to soak in and hold water when the rain falls. …