Water scarcity is a favourite topic for the headlines of doom, in company with overpopulation, climate chaos and nuclear war. The threat of a destabilising water crisis invariably wins attention in the annual Global Risks Reports published by the World Economic Forum.
In reality, our water woes reflect international political dysfunction as much as scarcity. If governments were more willing to collaborate in safeguarding the water cycle on which we all depend, and to share its beneficence fairly, they would discover that there is more than sufficient water to meet our needs.
In the absence of political leadership, water scares continue to populate the media. Scientists predict that the Middle East may become uninhabitable by 2100, largely on account of loss of freshwater. Residents of Cape Town, one of the world’s most affluent tourist destinations, spent the early months of 2018 counting down to “Zero Day”, the inauspicious moment when their taps would fail.
In 2014, the most recent year of data provided by the World Bank, global per capita availability of renewable freshwater from rivers, lakes, aquifers and rainfall averaged 6,000 cubic metres per annum, a potentially healthy figure, despite halving over the preceding 50 years. Only 9% of this resource is actually withdrawn, evidence of the worldwide abundance of freshwater.
However, freshwater is very unevenly distributed and scarcity is more realistically assessed within regions, countries or individual river basins. Seasonal variation can also be very significant. Amongst several approaches to a definition of water scarcity, there are two principal methods, each verifying that the reality experienced by millions of households is inconsistent with the statistics of global abundance.
The first approach considers the per capita availability of freshwater within a country or region, regardless of actual withdrawal. Availability of 1,000 cubic metres is regarded as the minimum necessary to meet the needs of households, agriculture, and industry – and to sustain local ecosystems.
A state of water scarcity exists below that threshold. Below 1,700 cubic metres, the less severe description of “water stress” applies. By way of illustration of regional extremes, renewable per capita freshwater availability in the US is over 8,800 cubic metres; in Jordan and Israel availability has fallen below 100 cubic metres. Water scarcity is most acute in the Middle East region where average availability is only a quarter of its level in 1962.
The second approach to a definition of water scarcity focuses on withdrawals as a proportion of available freshwater. Indicators approved for monitoring the Sustainable Development Goal for water adopt this method. A country that withdraws more than 25% of its availability is considered to be experiencing water stress; consumption of over 60% is classed as water scarcity.
There are 14 countries, nearly all in the Middle East, which consume more than 100% of their renewable water resources. Their aquifer levels are falling and they must seek alternative sources such as desalinisation.
The concept of “water security”, the inverse of scarcity, also lacks a consensual definition. It implies consistent and affordable access to unpolluted freshwater for households, agriculture and industry.
more Water Scarcity briefings (updated April 2018)
Water Energy Food Nexus
Causes of Water Scarcity
Climate Change and Water Scarcity
Solutions to Water Scarcity
Sustainable Development Goal for Water
Access to Safe Water
Source material and useful links