Band 8 model answer

Freshwater scarcity affects billions of people across multiple continents and is projected to worsen significantly in coming decades. Identifying its root causes is the first step towards building a coherent policy response.

The causes are both natural and human-made. Arid and semi-arid regions such as sub-Saharan Africa, the Middle East and parts of South Asia receive rainfall that is structurally insufficient for growing populations. Climate change is intensifying this by altering precipitation patterns and accelerating glacial melt, reducing the seasonal freshwater flows that communities have depended upon for centuries. Human activity compounds scarcity: intensive agriculture, which accounts for the vast majority of global freshwater withdrawal, frequently relies on inefficient flood-irrigation techniques that lose much water to evaporation. Rapid urban growth expands impermeable surfaces, reducing groundwater recharge while simultaneously increasing demand.

Solutions must address both supply and demand. On the supply side, governments and international bodies should invest in desalination technology for coastal regions and in large-scale rainwater harvesting and storage infrastructure in rain-fed areas. Upgrading municipal pipe networks to eliminate leakage, often responsible for losing a substantial share of treated water before it reaches consumers, offers immediate efficiency gains. On the demand side, introducing tiered pricing structures that charge heavy users progressively higher rates encourages conservation without penalising low-income households that consume modestly. Agricultural subsidies should be redirected to reward drip-irrigation adoption and drought-resistant crop cultivation. Regional water-sharing treaties, though politically complex, are indispensable where aquifers and river systems cross borders.

Progress will require genuine international cooperation as well as domestic policy reform, but the tools to manage scarcity already exist; what is lacking is consistent political commitment to deploy them at scale.