According to the International Water Management Institute, one in three people globally faces some form of water scarcity. With world populations continuing to grow, and industry and agriculture demanding increasing volumes of fresh water, the problem of water scarcity is certain to worsen. Beyond the immediate difficulties faced by individuals, extreme water scarcity can result in agricultural crisis and food scarcity, increased poverty, environmental degradation, and large-scale conflicts on the national and international level. As desalinization technology improves, the process may offer solutions to a host of water-related problems.
Because the effluent is discharged back into the sea, desalinization can have a large impact on the coastal environment. The brine effluent can raise saline levels in local sea water significantly, with salt potentially accumulating locally. The discharged water can also raise local water temperature, particularly if the desalinization plant uses a thermal process. Desalinization also uses chemical processes, which can result in chemical discharge. Ecological changes due to effluent can result in fish migration away from the area, and an increase in the presence of algae. The intake pipe also draws in smaller sea creatures, plankton, and larvae, reducing local populations.
Desalinization is more costly than gathering water from fresh sources, at times over five times the cost. Much of the cost comes from the considerable energy requirements. In some cases, it can be more cost effective to transport water over long distances from a fresh water source. In addition to the cost, the energy production results in pollution and greenhouse emissions in other locales.
The desalinization industry continues to look for ways to lower costs and and reduce harmful environmental impacts. Using alternative energy resources can diminish the ecological footprint, although generally at a higher price. Thermal desalinization methods can potentially recycle heat byproduct from other industries, including power stations. Reverse osmosis, a nonthermal process, may be improved with more permeable membranes. Many new processes are under development, including forward osmosis, low temperature thermal desalinization and geothermal desalinization.