Girl drinking water from a fountain
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Take claims desalination can fix water shortages with a pinch of salt

The technology can create more potable water, but is currently expensive and environmentally unfriendly.

The world already has a water scarcity problem. More than a billion people lack access to the water they need to meet their basic needs, and billions more struggle to get hold of as much water as they’d like for at least some parts of the year. But a situation that was already Not Good is getting substantially worse. Water scarcity is increasing due to a combination of factors: an expanding human population, modern life's increasing demands on water (for things like lawn care, daily showers and intensive farming), and climate change, which increases the intensity of droughts.

The interesting thing about water is that unlike many other resources our planet has a staggering amount of it: more than 70 percent of Earth is water. Unfortunately, the vast, vast majority of it is saltwater, which is entirely unsuitable for drinking, farming, washing or most other water needs. We can’t change that fact. But what we can change is the water itself via desalination technology, which turns saltwater into freshwater. The method has been embraced by several hot, dry places, including Saudi Arabia, California, and Israel. For the reasons we mentioned above, interest in it as a solution to water crises is ramping up.

This technology is no magic bullet, however. The downsides of desalination are pretty substantial. For one, it’s really expensive to do, which makes the tech inaccessible to many of the places in the world where water shortages are most acute. For another, it’s really not that great for the planet. Not only does it require a lot of energy (which usually comes from greenhouse-gas-causing fossil fuels), the process of pumping water out of the ocean and pumping the leftover salt back into it is harmful to marine life.

Some people think such flaws could be overcome. As a rule of thumb, technology can be made cheaper by investing in developing it or deploying it at scale. Fossil fuels could be replaced by renewable energy sources such as solar panels. The leftover salty brine could be kept out of the ocean, and perhaps even used for something productive. The question is whether businesses, governments and societies would be willing to spend all the extra resources, including a lot more money upfront, that these options would require.

If the world decided to significantly ramp up desalination, and certainly if they tried to make it greener and more efficient, then in the short term water prices for consumers would almost certainly rise significantly (or governments would have to commit a chunk of their budget to subsidising it). That could exacerbate the link between water access and wealth. Some people think a better and fairer route is to encourage people and businesses, especially rich ones, to cut way back on their water use.

Read our explainer on: is new technology always better?

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