As one of the most water-stressed countries in the world, Yemen faces social and economic disruption of legendary proportions.
National per capita access to water, estimated at 125 cubic meters per year, is already one of the lowest in the world yet is projected to drop to 62.5 cubic meters by 2025. A 900 million cubic meter shortfall in annual renewable water resources results in the extraction of groundwater at a rate that far exceeds natural recharge. Recent studies predict the depletion of multiple aquifers including the Sana’a basin by 2040. The loss of ground water for the country’s capital, and its 2 million residents could provoke a population exodus not seen in Yemen since the collapse of the Marib Dam in 575 A.D. This situation arises out of a classic “tragedy of the commons” problem: Yemeni citizens have drilled wells and pumped groundwater without regard to sustainability or future impact. While common ownership and management of water resources is a challenge in any country, in Yemen, it is a matter of survival.
Garrett Hardin's “Tragedy of the Commons” article in a 1968 edition of Science magazine provides an understanding of what a social good (like access to water) means and how that common asset can be managed for the benefit of the general public. Hardin explained that individual and absolute freedom to use a common asset results in a negative outcome. Preventing a negative outcome requires action to exclude or limit access to the common good. This excludability — which is the key to sustainability — can be achieved either through private or public ownership along with the potential to create cultural and reciprocity mechanisms that would encourage good stewardship.