The Importance and Uses of Water

Water is vital to life on Earth. It plays a key role in maintaining biological, physical, and human systems. Its unique physical and chemical properties make it essential for supporting all living organisms and regulating the planet’s climate.

1. The Role of Water in Supporting Life on the Planet

1.1 Universal solvent

• Water dissolves a wide range of substances, allowing chemical reactions to occur within living organisms.
• Nutrients and gases such as oxygen and carbon dioxide can be transported efficiently in solution.

1.2 Temperature regulation

• Water has a high specific heat capacity, meaning it can absorb and store large amounts of heat without major temperature change.
• This moderates the global climate and stabilises conditions in aquatic environments, allowing ecosystems to flourish.

1.3 The hydrological cycle

• The continuous movement of water through evaporation, condensation, and precipitation redistributes heat and sustains all ecosystems.
• This global system connects the atmosphere, biosphere, hydrosphere, and lithosphere.

1.4 The greenhouse effect and energy balance

• Water vapour is a natural greenhouse gas, helping to regulate the Earth’s temperature by trapping outgoing longwave radiation.
• Without this, average global temperatures would be too low to sustain life.

1.5 Surface processes and landscape formation

• Water drives geomorphological processes such as weathering, erosion, and transportation.
• It contributes to soil formation and nutrient cycling, which underpin terrestrial ecosystems.

2. The Importance of Water for Flora and Fauna

2.1 Cellular function

Water is essential for photosynthesis in plants and for respiration in animals.
It maintains cell turgor pressure in plants, enabling growth and structural support.

2.2 Metabolic reactions

• All biochemical reactions in living organisms occur in aqueous solutions.
• Water enables the transport of nutrients and waste within cells and throughout the body.

2.3 Habitat provision

Oceans, rivers, lakes, and wetlands provide habitats for an estimated 8.7 million species.
Many organisms are adapted to live in specific water conditions (e.g. temperature, salinity, flow rate).

2.4 Reproduction and survival

• Many species rely on water environments for reproduction (e.g. amphibians, fish, and aquatic plants).
• Migration and breeding cycles often depend on seasonal water availability, such as flooding in tropical wetlands.

3. The Importance of Water for Humans

3.1 Domestic and social uses

• Drinking, cooking, sanitation, and hygiene all depend on access to clean water.
• Safe water reduces disease transmission and supports improved health and well-being.

3.2 Agricultural use

• Around 70% of global freshwater withdrawals are used for irrigation.
• Reliable water supplies are critical for food security and global trade.

3.3 Industrial use

Water is vital for manufacturing, cooling, and energy production.
Industries such as textiles, chemicals, and food processing depend heavily on water supplies.

3.4 Energy production

Hydroelectric power uses flowing water to generate renewable energy.
Water is also used for cooling in thermal and nuclear power stations.

3.5 Economic development

• Rivers and lakes provide transport routes and support tourism, fishing, and recreation industries.
• Access to water resources often underpins patterns of economic development and population distribution.

4. Global Significance of Water

• Climate regulation: Water’s movement through the atmosphere redistributes heat and influences weather patterns.
• Carbon–water link: Photosynthesis and respiration link water and carbon cycles; both regulate global climate and ecosystem productivity.
• Sustainability challenge: Uneven water distribution and increasing demand place pressure on this finite resource, driving conflicts and the need for sustainable management.