Source: Scidev :http://www.scidev.net
The current metric for assessing water scarcity in Africa should be abandoned in favour of one tailored to local realities, argues Richard Taylor.
Ensuring that people have access to safe and affordable water supplies will be a major challenge for many developing countries as populations grow and agriculture and industry expand over the coming decades.
One of the greatest threats to water security is simply scarcity, where demand outstrips supply. This can result from geography, overexploitation or inadequate infrastructure, and climate change will put further pressure on the availability of freshwater in many parts of the world.
Nations or regions that are suffering from scarcity can achieve water security by the dual strategy of increasing water availability (such as with improved water storage, wastewater recycling or desalination) and cutting demand (such as with more efficient irrigation or food imports).
Failure to do so can have devastating consequences. Water shortages can ruin crops, increase the incidence of water-borne and water-related diseases, and damage aquatic ecosystems (the shrinking of Lake Chad being a prime example). Water scarcity can also fuel civil strife.
Policies that will help to avert these crises require robust ways of measuring water scarcity to target areas most at risk. But predicting water scarcity, particularly while the climate is changing, is difficult and at present the main method for assessing shortages — the so-called 'water stress index' — is not up to the task.