The largest country without a single river

At 2.15 million square kilometres, Saudi Arabia is the largest country in the world with no permanent waterways. The phenomenon is a direct consequence of the desert climate: rainfall is scarce and irregular, and high temperatures generate evaporation rates that prevent the formation of stable watercourses. What do exist are wadis, dry riverbeds that can fill temporarily during intense rainfall events.

To sustain a population of more than 35 million people in that environment, Saudi Arabia built the world's largest desalination infrastructure. The country produces more than 20% of globally desalinated water, with dozens of plants along the Red Sea and Persian Gulf coasts. The process is highly energy-intensive, generating enormous fossil fuel demand to sustain the water supply, although newer plants incorporate solar energy to reduce that cost.

The other pillar of supply is fossil aquifers, reserves of water accumulated thousands of years ago that are being depleted at a non-renewable rate. The horizon of those aquifers concerns planners: water that took millennia to accumulate is being extracted in decades. The extreme dependence on desalinated water and the overexploitation of fossil aquifers make water security one of the most delicate long-term strategic challenges for the region.