Global Water Supply Diminishes Despite Heavier Rainfalls

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An international study has found that the global water supply is diminishing at the same time when climate change is causing more rainfalls than ever. And the blame goes on the increasing dryness of soils, according to the new research, which presented a future world where drought would be the new normality.

The study, which is the most comprehensive global analysis of water supplies and rainfalls ever conducted, was carried out by a team headed by Professor Ashish Sharma at the University of New South Wales in Australia. The study based on real-time data gathered from more than 43,000 meteorological observatories and 5,300 river monitoring sites across 160 countries around the world, instead of relying on climate model simulations which might be uncertain.

“We expected rain to increase, as warmer air stores more moisture, and that’s what the climate models also predicted. What we didn’t expect is that, despite all the extra rain all over the world, the big rivers are drying up. We believe that the cause is the drying process of the soils in our watersheds. Before, when they were humid before a storm, they favored that the excess rain arrives towards the rivers, now they are drier and absorb more rain, reason why the quantity of water in the form of flow is smaller,” Professor Ashish Sharma said.

Global Water Supply Is Shrinking Despite Heavier Rainfalls

“Less water in our rivers means less water for cities and farms. And drier soils mean that farmers need more water to grow the same crops. Worse still, this pattern is repeated around the world, taking on serious proportions in places that were already dry. It’s extremely worrying,” the Professor added.

Out of 100 raindrops, about 36 drops are remaining in the form of “blue water,” which is the rain that enters lakes, rivers, and aquifers. The other two-thirds of the rainfall remains as soil moisture, known as “green water,” which is used by the Earth’s ecosystems. Due to global warming and higher temperatures, more water is evaporating from the world’s terrains, as dry soils suck more rain so that they leave less “blue water” for us to use in agriculture and for other purposes.

“It’s a double whammy. Less water is ending up where we can store it for later use. At the same time, more rain is overcoming drainage systems in towns and cities, leading to more urban flooding,” concluded Professor Sharma.


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