Tag: Fresh water

Counting on … day 1

7th January 2026

How do we protect and preserve fresh water supplies – part 2

Land use changes, especially things such as deforestation and urbanisation, have aggravated the problem – 

“Deforestation, agriculture, and urban expansion have greatly changed the way land stores and moves water. When forests are cleared or soils are sealed under concrete, they lose their ability to hold green water — the moisture that plants rely on. This weakens local rainfall, increases runoff, and can intensify both floods and droughts. Changes to land systems also affect regional weather patterns, such as monsoons, and create feedback loops that further influence the climate.” (1)

Reducing or indeed eliminating such land use changes is clearly beneficial for the wellbeing of the planet. We can go further by reversing the changes by both protecting and increasing land uses that capture and store – eg through reforestation,  restoring peatlands and wetlands, re-wriggling  rivers (ie allowing them to flow freely and more slowly across a greater expanse of the flood plain, re-establishing water meadows, limiting the extraction of water to protect lakes and aquifers etc.

These nature based solutions not only protect supplies of fresh water, they also protect and enhance biodiversity and reduce the risk of flooding, creating a better environment for us to enjoy.

(1) https://www.planetaryhealthcheck.org/boundary/freshwater-change/

Counting on … day 208

19th December 2025

What should we be doing? – 1

Reviewing and redesigning the way we use fresh water so as to conserve and protect this precious resource for the benefit of all.

“Human use of water, especially for agriculture, is [a] major driver of freshwater change. Irrigation alone accounts for about 70% of all freshwater withdrawals, and around 90% of the water that is consumed and not returned to the source. Large-scale river diversions, dams, and groundwater pumping have dramatically altered the flow and storage of blue water, lowering water levels in rivers, lakes, and aquifers and degrading aquatic habitats.” (1)

Where dams are placed and how the flow of water downstream is controlled is very important if fair access to water is to be ensured. One of the main factors causing Iran to be so short of water and why in parts of Tehran there is a real risk of taps literally running dry. Nations upstream of Iran have set up dams and extract so much water, that downstream rivers such as the Tigris have severely reduced flow. 

How water is used for agriculture also needs to be controlled and consideration given as to which crops are grown, and whether there are more water efficient plant varieties and methods of farming.

The Aral Sea has already been destroyed by agricultural water extraction (mainly for cotton which is a very thirsty crop – 15,000 tonnes of irrigation water per hectare) and now the Caspian Sea is similarly under threat. 

Consideration also needs to be given to the place of livestock farming. Globally 30–40% of fresh water is used to provide 16% of the food obtained as meat, eggs, and dairy products – the vast majority of this is water used in growing food crops for the animals.

All foods have a fresh water footprint. The size will vary with location. Strawberries grown for example in Spain will have a higher water footprint than those grown in the cooler climes of the UK. 70% of Spanish strawberries are grown in the Doñana region where the extraction of water is depleting the water in the region’s biodiverse wetlands.

Governments and farmers and scientists need to work together to ensure against the over-extraction of water. Different farming methods and different crops etc that use less water should be utilised.

As customers we too can contribute by shaping our diets around foods with lower water footprints. 

You can find more information online: eg-

https://www.bbcgoodfood.com/howto/guide/your-diet-contributing-water-scarcity

Or look at the Planetary Health Diet. Its researchers estimate that following this optimised diet produces a lower water footprint of up to 30%.

https://www.bbcgoodfood.com/health/special-diets/what-is-the-planetary-health-diet
The Planetary Health Diet

(1) https://www.planetaryhealthcheck.org/boundary/freshwater-change/

Counting on … day 206

17th December 2025

Only 2.5% of the Earth’s water is fresh water – the rest is salt water found in the seas and oceans.

Fresh water exists in two forms, blue water and green water.

Blue water is the water that is in rivers, lakes , underground aquifers and as frozen water in glaciers and ice sheets. Amazingly about 60% of blue water is locked away as ice.

Green water is the water stored in the soil and drawn up by plants. 

Every year some 500,000km3 of water evaporates from the surface of the oceans, with 450,000km3 returning as precipitation directly back into the ocean(usually within a period of about 9 days) and 50,000km3 falling on land. 

“The highest rate of evaporation from the oceans occurs in winter for both the Northern and Southern Hemispheres. The location of greatest evaporation is found on the east coasts of continents. This is due primarily to winter storms that move off the east coasts of continents, which tend to have strong winds. These winds help carry water vapor away from its source, thereby allowing more evaporation to take place.

“Another factor is the warm ocean currents that move pole-ward along the east coasts of continents. The cold winter-time air masses that move over the water allow for large differences in air and sea temperatures, so evaporation is also large. When these differences in air and sea temperatures are then combined with strong winds, it makes evaporation in these regions very efficient.” (1)

Water molecules from the ocean would struggle to reach the inner parts of the continents. Here precipitation is dependent on moisture that has been released by plants through evaporation, forming clouds etc. Plants provide about 70,000km3 of such precipitation. Vegetation cover is key to ensuring that precipitation spreads right across continents. 

The other key source of water for inland areas is from melting snow and ice: high mountain regions capture precipitation and then release it throughout the year as meltwater-fed rivers. Water molecules that are exist within these frozen states may take a thousand years to complete the journey from precipitation to their return to the ocean! This is also highlights as we loose glaciers because of global warming, they will be hard to replace.

  1. https://www.noaa.gov/jetstream/max-what-cycle

Counting on … day 205

16th December 

Fresh water is essential for life, but are we using it wisely?

“A new analysis of freshwater resources across the globe shows that human activity has pushed variation in the planet’s freshwater cycle well outside of its pre-industrial range. The study shows that the updated planetary boundary for freshwater change was surpassed by the mid-twentieth century. In other words, for the past century, humans have been pushing the Earth’s freshwater system far beyond the stable conditions that prevailed before industrialisation.” (1) 

We are seeing more extreme wet and more extreme dry conditions across the globe. Ingo Fetzer at the Stockholm Resilience Centre notes: “Water extremes, such as droughts and flooding, can have significant impacts on ecosystems and biodiversity that function are essential for human societies. However, human activities, including agriculture, urbanisation, and climate change, influence the water cycle and exacerbate extreme events. By understanding and mitigating these factors, we can work to protect and preserve our planet’s vital water resources and maintain biodiversity.” (1)

  1. https://www.stockholmresilience.org/research/research-stories/2024-03-06-freshwater-planetary-boundary-has-been-crossed-since-the-mid-twentieth-century.html