Crisis! Freshwater
Why the world's supply of fresh water is under growing pressure — and what needs to change
A. Fresh water — the water suitable for drinking, irrigation, and industrial use — accounts for less than three percent of all the water on Earth, and the great majority of this is locked in glaciers, ice caps, and deep groundwater aquifers that are inaccessible or impractical to exploit. The fraction that circulates through rivers, lakes, wetlands, and accessible groundwater — the fresh water that human societies depend on — amounts to less than one percent of the global total. Demand for this resource has more than tripled over the past century, driven by population growth, agricultural expansion, and rising industrial and domestic consumption, and in many regions the rate of withdrawal already exceeds the rate at which natural systems can replenish it.
B. Agriculture is by far the largest consumer of fresh water, accounting for approximately 70 percent of global withdrawals. The irrigation of crops in arid and semi-arid regions — where evapotranspiration losses are high and rainfall unreliable — is the primary driver of freshwater depletion. In many of the world's major agricultural regions, including the High Plains of North America, the Indus Valley of South Asia, and the North China Plain, irrigation systems are drawing from deep fossil aquifers — groundwater accumulated over thousands of years during wetter climatic periods — that are being depleted far faster than any natural recharge process could replenish them. The consequences of aquifer exhaustion for food production in these regions would be severe.
C. Urban demand for fresh water is growing rapidly as cities expand. Municipal water systems in many developing countries are characterised by aging infrastructure, high leakage rates, and insufficient treatment capacity. Water utilities in some cities lose 40 to 50 percent of their supply through leaking pipes before it reaches any consumer. The combination of population growth, urbanisation, and infrastructure deficit has produced acute water shortages in many cities, including Cape Town, where reservoir levels fell so low in 2018 that authorities planned to shut off the municipal water supply entirely — an event referred to as 'Day Zero' — before emergency conservation measures averted the immediate crisis.
D. Climate change is exacerbating freshwater stress through multiple pathways. Higher temperatures increase the rate of evaporation from soils, rivers, and reservoirs, reducing the effective water available even where precipitation totals do not change. Glaciers and snowpacks that act as natural reservoirs — storing precipitation in winter and releasing it gradually through the summer — are retreating across the world's major mountain ranges, threatening the water security of hundreds of millions of people who depend on glacial meltwater during the dry season. Changes in rainfall patterns are intensifying both floods — which overwhelm infrastructure and contaminate drinking water — and droughts, with less predictable seasonal distribution.
E. Improving water use efficiency in agriculture is considered by most analysts to be the most important single lever available for addressing global freshwater stress. Drip irrigation, which delivers water directly to plant roots at low flow rates, can reduce agricultural water consumption by 30 to 50 percent compared with flood irrigation while maintaining or improving crop yields. The adoption of drip and other precision irrigation technologies has been constrained by high upfront costs, lack of technical knowledge among smallholder farmers, and the absence of incentives to conserve water where it is priced far below its true economic value.
F. Desalination — the removal of salt from seawater or brackish water to produce fresh water — is expanding rapidly as a water source in coastal areas and island nations with limited freshwater resources. The technology is reliable and produces high- quality water, but it is energy-intensive: large desalination plants typically consume between three and ten kilowatt-hours of electricity per cubic metre of water produced. In regions that depend on fossil fuels for electricity generation, the environmental cost of desalination is considerable. Where plants can be powered by renewable energy — as in some projects in the Middle East and North Africa — the environmental profile improves significantly.
G. Addressing freshwater scarcity ultimately requires changes in governance as well as technology. Water is managed under a patchwork of national and local laws, many of which were written in eras of perceived abundance and do not adequately price the resource to reflect its scarcity. International freshwater law — governing the use of rivers, lakes, and aquifers shared between countries — is fragmented and poorly enforced, creating conditions for conflict between upstream and downstream users. Strengthening water governance at every level — from international river basin agreements to local pricing reforms — is as important as any technological innovation in ensuring that finite water resources are allocated fairly and used sustainably.