Water scarcity is projected to worsen significantly over the coming decades, driven by a combination of climate disruption, surging demand, groundwater depletion, pollution, and aging infrastructure. Only about 1% of Earth’s total water is liquid freshwater accessible to humans, and the pressures on that slim supply are compounding. Here’s what’s behind the growing crisis.
Earth’s Freshwater Supply Is Tiny
Over 96% of all water on Earth is saltwater. Of the remaining freshwater, most is locked in glaciers or buried deep underground where it can’t be reached. Rivers, the source most people depend on for drinking water, agriculture, and industry, hold roughly 509 cubic miles of water. That’s about one ten-thousandth of one percent of the planet’s total. Fresh lakes add another 21,830 cubic miles, and swamp water contributes a small fraction on top of that.
This means humanity is drawing from an extraordinarily narrow slice of the planet’s water. Any pressure that shrinks supply or increases demand tips the balance quickly, and right now, multiple pressures are hitting at once.
Climate Change Is Reshuffling Rainfall
Rising global temperatures accelerate evaporation, which in turn increases total precipitation worldwide. That might sound like good news, but the extra rain and snow don’t fall evenly. Some coastal regions are getting wetter while the interiors of continents are drying out. Traditional rain belts and desert boundaries are shifting, meaning areas that historically had reliable water supplies may lose them, while other regions face flooding they aren’t equipped to handle.
Mountain glaciers and Arctic ice sheets have shrunk dramatically over the past century. Many communities in South America, Central Asia, and the western United States depend on seasonal snowpack melt to fill rivers and reservoirs during dry months. As glaciers disappear, that natural storage system vanishes with them, leaving rivers lower precisely when demand peaks in summer.
Agriculture Dominates Water Use
Farming accounts for roughly 70% of all freshwater withdrawals worldwide, dwarfing industrial use (just under 20%) and household use (about 12%). Most of that agricultural water goes to irrigation. As the global population grows toward an estimated 9.7 billion by 2050, food production will need to increase substantially, and with it, water demand.
The challenge is sharpest in arid and semi-arid regions where crops already rely heavily on irrigated groundwater. In many of these areas, farmers are pumping water out of aquifers far faster than rain can replenish them. Shifting diets toward more water-intensive foods like meat and dairy in developing economies adds further pressure. Without major gains in irrigation efficiency, agriculture’s share of water withdrawals will continue to strain supplies that other sectors also need.
Groundwater Is Being Drained Faster Than It Refills
Aquifers serve as underground savings accounts: water seeps in slowly over decades or centuries, and humans withdraw it through wells. In many of the world’s most productive farming regions, withdrawals far exceed the natural recharge rate. Global groundwater depletion (the gap between what’s pumped out and what filters back in) is projected to reach 887 cubic kilometers by 2050, roughly 61% higher than 2021 levels.
The most threatened aquifers sit beneath semi-arid and arid regions where recharge is naturally low and agricultural pumping is intense. Parts of India, the Middle East, North Africa, and the central United States are already watching water tables drop year after year. Once a deep aquifer is depleted, it can take centuries to recover, if it recovers at all. Some aquifers compact permanently as water is removed, losing their capacity to hold water in the future.
Pollution Shrinks the Usable Supply
Water doesn’t have to physically disappear to become unavailable. Pollution effectively removes water from the usable supply. Globally, 42% of household wastewater was not safely treated before being discharged in 2022, releasing an estimated 113 billion cubic meters of inadequately treated sewage into rivers, lakes, and coastal waters each year.
Industrial wastewater treatment is even harder to track. Among the 22 countries that reported data (covering just 8% of the global population), only 27% of industrial wastewater was safely treated. The rest carried chemicals, heavy metals, and other contaminants into waterways. Contaminated surface water and groundwater can’t be used for drinking or irrigation without expensive treatment, and in many lower-income countries that treatment capacity simply doesn’t exist. As industrial activity and urbanization expand, pollution will take an even larger bite out of the freshwater that’s technically available.
Aging Infrastructure Wastes What We Have
Even in wealthy countries, a significant share of treated, drinkable water never reaches a tap. It leaks out of aging pipes, faulty connections, and poorly maintained distribution systems. This “non-revenue water” represents both a physical loss and an economic one for utilities.
The scale varies widely. In California, large water systems lose about 9% of their supply to leaks, while smaller systems lose closer to 15%. In Georgia, losses run much higher: around 21% for large systems and nearly 39% for small ones. In many developing countries, leakage rates of 40% to 60% are common. Fixing underground pipe networks is expensive and slow, and many cities are falling further behind as infrastructure ages faster than it can be replaced.
Shared Rivers Create Political Flashpoints
More than 260 river basins cross international borders, and as water becomes scarcer, competition between countries sharing the same source intensifies. Three basins illustrate the pattern clearly. In the Nile basin, Ethiopia’s Grand Ethiopian Renaissance Dam has strained relations with downstream Egypt and Sudan, both of which depend on Nile flows for agriculture and drinking water. In South Asia, the decades-old Indus Waters Treaty between India and Pakistan is struggling to address modern demand levels and climate-altered river flows. And in the Euphrates-Tigris basin, unilateral dam construction by Turkey and reduced flows into Iraq and Syria have deepened regional instability.
These disputes aren’t just diplomatic irritants. When upstream countries control dam releases or divert flows, downstream populations can face sudden shortages that affect food production, electricity generation, and basic sanitation. Climate change makes these tensions worse by altering the total volume of water in shared systems, turning what were manageable disagreements into potential crises.
Desalination Helps but Has Limits
Turning seawater into freshwater is one obvious solution for a planet covered in ocean, but the energy cost is steep. Treating conventional surface water requires about 0.2 to 0.4 kilowatt-hours per cubic meter. A modern seawater reverse osmosis plant needs 3.5 to 4.5 kilowatt-hours per cubic meter once pre-treatment and post-treatment are included. That’s roughly 10 to 20 times more energy.
For wealthy, water-scarce coastal nations like Saudi Arabia, Israel, and Australia, desalination already plays a major role. But for landlocked countries or lower-income nations, the capital investment and ongoing energy bills make large-scale desalination impractical with current technology. There’s also the problem of brine, the concentrated salt byproduct that must be disposed of without damaging marine ecosystems. Desalination will be part of the answer, but it won’t solve the problem for most of the world’s water-stressed populations in the near term.
Why These Pressures Compound
None of these factors operates in isolation. Climate change reduces snowpack, which lowers river flows, which pushes farmers to pump more groundwater, which depletes aquifers faster. Population growth increases both food demand and urban wastewater, polluting the surface water that remains. Leaky infrastructure wastes the treated water that cities manage to produce. And political disputes slow the cooperative management that shared river basins desperately need.
The math is straightforward: demand is rising on multiple fronts while the usable supply is shrinking. By mid-century, billions of people will live in regions where the gap between water availability and water need has become a defining constraint on daily life, economic growth, and political stability.