Global Water Distribution, Consumption and Insecurity

• Geographers also use the Water Balance Equation to track water in a system:

• (Where P = Precipitation, Q = Runoff, E = Evapotranspiration, and $\Delta S$ = Change in Storage).

Reasons for Increasing Water Consumption

• Every time you buy a cotton T-shirt or eat a burger, you are consuming hidden virtual water embedded in its production.
• Global water consumption skyrocketed from 1.22 trillion m³ in 1950 to over 4 trillion m³ in 2018. The primary driver is population growth, with the global population hitting 8 billion in 2022 and projected to reach 9 billion by 2037.
• More people directly increase the basic demand for drinking and sanitation, requiring a minimum of 20L per person daily.
• Economic development is another major reason for rising demand. As countries transition from Low-Income Countries (LICs) to Newly Emerging Economies (NEEs), disposable income rises.
• This leads to the purchase of water-intensive appliances; in the UK, domestic demand has risen 70% since 1985, with the average person using 150-152L per day and 98% of households owning a washing machine.
• Development also causes a dietary shift toward meat consumption. Producing 1kg of beef requires 15,000L of water, compared to just 1,200L for 1kg of maize.
• Finally, rapid urbanisation and industrial growth in NEEs require massive volumes of water for manufacturing, piped city water, and cooling power stations. Globally, agriculture still dominates usage at 69-70%, followed by industry at 19-20%, and domestic use at 10-12%.

Factors Affecting Water Availability

• Why do some areas with relatively high rainfall still suffer from severe water shortages? The availability of water is controlled by a complex mix of physical and human factors.
• Physical factors include climate and geology. High precipitation creates a surplus, but high rates of evapotranspiration in arid regions cause a deficit.
• Geology is crucial: permeable rocks like chalk allow water to infiltrate and form underground aquifers.
• In contrast, impermeable rocks like granite do NOT allow infiltration, leading to surface runoff that is harder to capture.
• A lack of available water due to these natural climatic or geological conditions is known as physical water scarcity.
• Human actions also drastically limit water supply. Pollution severely reduces the availability of safe water; globally, 80% of wastewater is discharged untreated.
• Agricultural fertilisers cause eutrophication, and industrial chemicals contaminate rivers.
• Over-abstraction, which means taking water faster than it naturally replenishes, affects 20% of global aquifers. Over-abstraction in Mexico City has caused the ground to sink by up to 40cm per year, breaking underground pipes.
• In Rajasthan, India, extraction at a Coca-Cola plant caused the water table to drop 15m in 10 years, while Lake Chad has lost 90% of its surface area due to both drought and irrigation.
• Finally, poverty and poor infrastructure create economic water scarcity, where water exists but is inaccessible. In the UK, 20% of water is lost to pipe leakage, while LICs simply lack the funds to build treatment plants or deep boreholes.

The Impacts of Water Insecurity

• Understanding water insecurity explains why a shared river can spark international conflicts and devastate global supply chains.
• Water insecurity has severe, cascading impacts on human health. Globally, 2.4 billion people lack adequate sanitation.
• A lack of clean water leads to the spread of waterborne diseases like cholera and typhoid, resulting in the deaths of 289,000 children under 5 annually from diarrhoeal diseases.
• Economically, water shortages cripple industry and agriculture. In China, water shortages cost US$40 billion a year in lost production.
• In agriculture, insecurity lowers crop yields and prevents farmers from transitioning from subsistence to commercial farming.
• A clear chain of reasoning shows how water insecurity limits development: lack of water leads to disease, which reduces workforce productivity, causing a drop in industrial and agricultural output, and ultimately slowing economic growth.
• Severe pollution also causes insecurity. The River Ganges in India receives 1 billion litres of raw sewage daily, alongside toxic chromium from leather tanneries.
• Water insecurity also triggers severe conflicts over resources. Transboundary conflicts occur internationally, such as the dispute between Ethiopia and Egypt/Sudan over the Grand Renaissance Dam on the Nile, or India's Farakka Barrage reducing flow into Bangladesh.
• Local conflicts also erupt over groundwater. In the Ica Valley of Peru, large-scale asparagus farming for export depleted local aquifers, drying up wells for 18,000 local residents, while water privatisation in Bolivia triggered the Cochabamba water wars.