Desalination: Drinking the Ocean

Reverse osmosis pushes seawater through membranes with pores so fine that salt cannot pass. It is the dominant desalination technology, and costs have dropped roughly 80 percent since the 1990s. Israel now draws about 80 percent of its domestic water from desalination, turning a once water-scarce nation into one with a surplus.

Desalination is energy-intensive — one cubic meter of freshwater requires 3 to 4 kilowatt-hours. The brine problem compounds this: every liter of freshwater produces 1.5 liters of hyper-salty discharge that damages marine ecosystems if not properly managed.