A New Hope? Moisture Farming as a Long-Term Alternative Water Source
Desert-focussed moisture farming, similar to the work practiced by the fictional Star Wars character Luke Skywalker, is no longer a method of survival restricted to Hollywood. Researchers have, over the years, developed devices that take moisture from humid climates and convert it into drinkable water. This involves cooling humid air to produce condensation and, thus, water.
Water scarcity already affects every continent on the planet, with at least one-fifth (1.2 billion people) of the world’s population suffering from water scarcity and an additional 500 million people set to share the same fate. Water scarcity has been increasing parallel to population growth and, with the world’s population set to reach 9.7 billion by 2050; water stress is likely to be one of the most pressing security concerns for both states and individuals alike.
In India, a growing number of aquifers are disappearing. According to the World Bank, India is the largest user of groundwater in the world, with more than 60 per cent of agriculture and 85 per cent of drinking supplies relying on groundwater. Parts of India have approximately 20 years before groundwater supplies are outstripped by demand, leading to a critical water situation that will jeopardise the country’s food and water security. Wasteful over pumping has been cited as the chief reason for the worsening crisis. Peru is another country that is becoming increasingly water scarce. In the Ica Valley, groundwater has steadily become an endangered resource, mainly because of the profitable crop, asparagus, which many argue should be outlawed because of the high levels of water needed to grow it. As a result, groundwater is quickly running out.
Vietnam has recently suffered drought as a result of a water shortage along the 4,800 kilometre Mekong River. Given that 80 per cent of its total water supply is used on agriculture and that pollutants have continued to enter the country’s potable water supplies, an alternative water source is needed. Finally, in Israel, the allocation of water to a growing population has placed the desert country’s supply under greater stress. Though desalination plants account for much of Israel’s water supply and smart policies like drip irrigation have mitigated the agricultural impact on its water stores, sharp falls have been registered in the levels of the country’s aquifers leading to an increasingly water-stressed Israel.
In common with the examples listed above, water-stressed countries tend to have a common feature: their traditional water sources are not sustainable. As previously noted, existing ground and surface water supplies are slowly disappearing and, thus, are becoming much harder to obtain. Groundwater-reliant communities have little choice but to sink wells in an attempt to find water. These wells, however, are very costly and must be sunk anywhere between 150 to 460 metres below the surface, depending on the terrain. Such ventures are not easy to fund, especially in developing countries, and the fact that today’s wells must be dug ever deeper confirms that they are not a sustainable practice. Diminished or polluted water supplies also require people, usually women, to travel for water and, even then, the water may still be polluted. It is estimated that people in the Horn of Africa spend approximately 40 billion hours per year travelling to find water.
Though moisture farming is not a perfect solution, it can help to offset some of these challenges. It is not a very costly infrastructure project but, at the same time, it catches large amounts of water. Condensation towers in Ethiopia, for instance, are little more than cages of bamboo or dried, interwoven rushes with nylon mesh installed inside. Condensation then forms on the mesh and falls into a basin at the bottom attached to a tap. Architecture and Vision, the group behind the Ethiopian project, believes that around five to six people are needed to set up these moisture towers, offsetting the need to drill expensive wells 460 metres down. The towers catch around 30 to 40 litres of water per day.
In Lima, Peru, the University of Engineering and Technology built a billboard that cost only US$1,200 to install and which houses five condensers that cool warm air and turn it into a liquid. Installed in December 2012, it had, by March 2013, produced 9,450 litres of water; about 96 litres of water per day. Within a region with 90 per cent humidity and 12.9 millimetres of annual rainfall, moisture farming is already proving to be a viable long-term water source.
Moisture farming in humid, and now dry, conditions has long-term promise that is no longer a solution practiced in a galaxy far, far away.