Skip to 0 minutes and 9 secondsDemand for water is rising inexorably through a combination of population growth, economic development, and changing consumption patterns. Over the past 100 years, global water use has increased nearly eight times. Traditionally, the largest demand for water comes from agriculture, around 70%. But demand for industrial users and domestic use is now increasing more rapidly. Water for use in power generation is also an important source of demand. Rising demand for energy and for food will increase future demand for water supplies, presenting important challenges for the future. We should also remember that our ecosystems need water to survive, what is known as environmental water requirements. Looking forward, it is estimated that water demand will continue to rise.

Skip to 0 minutes and 55 secondsThis is mainly ascribed to demand by industry and households, which taken together will represent an almost threefold increase by 2050. As our available water resources reach their physical limits, so water security may be adversely affected. The location of water demand is changing, as well. Demand is currently highest in those countries with the highest income levels. But demand is now rising more strongly in countries with low and middle incomes. Across the world, the amount of water used by individuals varies. In the UK, the average person uses 140 litres per day. Yet in Cape Town, South Africa, residents have been restricted to just 50 litres per day in 2018 owing to the effects of drought.

Skip to 1 minute and 37 secondsAs we said earlier, not all fresh water is accessible. Some is locked in the polar ice caps, and much is stored in rivers and lakes too far from humans to be used. Of the water that is available, there are many potential sources. Most is abstracted from surface stores, typically from rivers, lakes, or dams. Some is taken from groundwater, stored in natural aquifers. However, in many parts of the world, current levels of abstraction are unsustainable, limiting the amount of water available for ecosystems with significant consequences for what is, in fact, a life support system. To meet increasing water demand, new technology is being used to extract fresh water from our seas and to recycle water.

Skip to 2 minutes and 18 secondsOther techniques, such as rainwater harvesting, can meet small scale local needs. Agriculture can reduce the amount of water it uses, for example, through better timing of irrigation to minimise evaporation losses or by using crops that are less water demanding. Industry can be less wasteful and more innovative. We can also manage our infrastructure to reduce water leaking from pipes. In England, three billion litres of water a day are lost through pipe leakage. That's equivalent to the amount of water use by 20 million people or more than a third of the total population of England. We can also change our behaviours and change the way that we reuse or use water itself.

Water availability

In this video Dr Adrian Healy explains how we exploit water, and how water is used across the world.

Freshwater is essential for healthy lives and a healthy environment.

Ecosystems depend on the availability and quality of water to thrive, and as humans we also depend on water for the food we eat, the energy we generate, the goods we produce and, of course, our drinking, cooking and cleanliness.

This makes the security of our water resources, critical for the well-being of ourselves and our planet.

Not all freshwater is accessible, some is too remote or difficult to reach. Over 68% of the fresh water on Earth is found in icecaps and glaciers, and just over 30% is found in ground water. Only about 0.3% of our freshwater is found in easily accessible lakes, rivers, and swamps.

Of the freshwater that’s available, it’s estimated that we already use more than half of this. To secure a more reliable water supply, we’ve extensively relied on our engineering skills to the extent that we’re now storing five times the total volume of all the Earth’s rivers behind dams, and we release almost their equivalent volume of wastewater each year.

Over to you

  • Do you try to save water at home? If so, how?

Let us know in the comments.


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The Challenge of Global Water Security

Cardiff University

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