Fresh water is naturally occurring water with low concentrations of dissolved salts, distinct from seawater and brackish water. It originates from precipitation and is found in various forms, including rivers, lakes, wetlands, groundwater, glaciers, and ice sheets. Despite its widespread presence, fresh water constitutes less than 3% of Earth’s total water resources, with about 70% locked in glaciers and ice caps, making it largely inaccessible. The small fraction readily available is indispensable for the existence and well-being of all life on Earth.
Sustaining Human Life
Fresh water sustains human life, primarily through direct consumption and its contribution to public health. The human body is composed of 50% to 70% water, relying on it for nearly all major systems to function properly. Water transports nutrients and oxygen to cells, flushes out waste, regulates body temperature, lubricates joints, and protects sensitive tissues and organs.
Adequate daily fluid intake is generally recommended to prevent dehydration, which can lead to fatigue and impair normal bodily functions. Beyond direct consumption, fresh water is integral to public health through sanitation and hygiene practices.
Access to clean fresh water is necessary for preventing the spread of waterborne diseases caused by pathogenic microorganisms. These illnesses result from contaminated drinking water or contact during bathing or washing. Annually, waterborne diseases affect millions of people, leading to substantial healthcare costs and, in some cases, fatalities. The lack of safely managed drinking water and sanitation services contributes significantly to this global health burden.
Supporting Food Production
Fresh water is a fundamental input for global food production, underpinning agriculture, livestock farming, and aquaculture. Agriculture alone accounts for approximately 70% of freshwater withdrawals worldwide. Much of this water is used for irrigating crops, ensuring food security by supplying plants with moisture for growth, especially in arid or semi-arid regions. Poor water management can lead to significant waste, potentially up to 40% of the water used in agriculture.
Raising livestock also demands substantial fresh water. Animals require water for direct consumption, cleaning, and maintaining animal health. The water footprint for livestock products can be considerably higher than for crops, reflecting intensive water use.
Aquaculture, or fish farming, relies on a plentiful supply of high-quality fresh water. While total water withdrawals for aquaculture may seem smaller compared to agriculture, it is a water-intensive endeavor, particularly for pond-based systems requiring large volumes. The availability of fresh water directly influences the ability to produce sufficient food to feed a growing global population.
Powering Industry and Economy
Beyond human consumption and food production, fresh water is an indispensable resource for various industrial processes and economic activities. Industries utilize water for manufacturing, cooling systems, and as a solvent in production cycles. For example, water is used in the production of goods, acting as a low-cost medium for transporting materials, and as an ingredient in chemical processes.
Energy generation also depends heavily on fresh water. Hydropower plants harness the flow of water to produce electricity, and thermal power plants use water for cooling. Water is circulated to dissipate heat, preventing equipment from overheating.
Mining operations are another sector with significant water requirements. Water is used for mineral extraction, processing, transport of ore and waste in slurries, dust suppression, and cooling machinery. Although mining accounts for a smaller percentage of overall water withdrawals compared to agriculture, it is important for extracting economically important materials. The availability and management of fresh water directly influence the profitability and sustainability of these industries, contributing to the broader economy.
Maintaining Ecosystems and Biodiversity
Fresh water maintains the health and diversity of natural ecosystems, indirectly supporting human well-being. It sustains a variety of freshwater ecosystems, including lakes, ponds, rivers, streams, and wetlands. These environments provide habitats for countless species of plants and animals, including a significant portion of the world’s fish species. For example, freshwater ecosystems are home to 41% of the world’s known fish species. They support complex food webs and contribute to overall ecological balance. Healthy freshwater systems allow for natural processes such as nutrient cycling, where water helps transport and transform important elements.
Fresh water also influences regional climate regulation by affecting local humidity and temperature patterns. The interconnectedness of water, land, and atmosphere means that changes in freshwater availability can have cascading effects on weather systems and climate. Maintaining these natural functions helps preserve the rich biodiversity of our planet, which in turn provides various benefits, from clean air and water to recreational opportunities.