What’s going on here?
Earth’s fresh water is getting saltier, hit by the double trouble of rising sea levels and increased salt pollution from land. New research shows that sea levels are rising faster than expected, threatening drinking water which already suffers salt contamination from land. And climate change is making it worse on both counts.
What does this mean?
Humans love salt; from seasoning our food to de-icing the roads. For example, in the US almost half of the salt used goes on snowy and icy roads and then into the surrounding environment. Massachusetts alone uses almost half a million tonnes of the stuff every year.
But all this activity can disrupt the planet’s natural ‘salt cycle’, meaning salt builds up in freshwater ecosystems and isn’t being washed out. Rainfall usually rinses excess salt from freshwater systems, but the climate crisis is creating more drought conditions which prevent this flushing effect.
At the same time, global sea levels rose faster than expected in 2024, mostly due sea water getting warmer and expanding. Rising seas can lead to ‘saltwater intrusion’ when seawater floods low lying areas or breaches underground water sources like aquifers.
That means salt is coming from both land and sea and meeting in the middle, creating a double threat to freshwater tidal basins.
Why should we care?
Too much salt in our water can be toxic to both humans and wildlife. Salt contamination causes some plant species to dry out, and can cause health risks for frogs, fish and insects. In higher concentrations, salt in drinking water has also been linked to high blood pressure, chronic kidney disease, dementia and fertility issues.
Another new study has also found that when water gets saltier, it can trigger chain reactions that create knock-on impacts. For example, saltwater can corrode pipes used for drinking water or power supplies, and contaminate soils and kill crops.
There are groups in the US pushing to use less salt on icy roads, and come up with alternative ways to keep highways drivable. For example, different types of salt (other than trusty sodium chloride) are more effective and go further. And in Massachusetts, new technologies such as porous pavements are having some success at reducing ice build up in the first place.
Be curious
📡 Read NASA’s research on 2024 sea level rise
🚗 Need to de-ice a driveway? Find out how much salt you need – it’s probably less than you think
🦢 From the Curious archives: Wonderful wetlands and why their conservation is a priority
Featured image by Jamie Street on Unsplash.
