The world’s coastal areas are facing a growing and often ignored danger: thesalt water intrusion in aquifers. These natural reservoirs of fresh water, on which they depend over 2.5 billion people for water supply, risk becoming unfit for human and agricultural consumption due to this progressive contamination.
A recent study reveals that, by 2100The 77% of the coastal aquifer will suffer significant salt water infiltration. Climate change, with the rise in sea levels and the reduction in groundwater recharge, is among the main causes of this phenomenon.
Saline infiltration occurs when the delicate balance between fresh water and salt water is interrupted. In coastal aquifers, in fact, fresh water naturally repels sea water, maintaining a stable separation called freshwater-saltwater interface. However, rising sea levels and reduced aquifer recharge, exacerbated by climate change, are pushing salt water deeper and further from the coast.
The phenomenon at a global level: 3 out of 4 coastal aquifers at risk
For the first time, researchers have quantified the magnitude of the risk on a global scale. Using data from over 60,000 coastal watershedsthe study predicts that by 2100:
In particularly vulnerable regions such as Southeast Asiawhere large populations live in flat areas at low altitude, the situation is critical. Countries like Vietnam, Bangladesh And Indonesia they risk losing large portions of their freshwater reserves, compromising supplies for millions of people.
In Europe and the United States, areas such as Florida and the regions of Gulf of Mexico they face a double threat: reduced recharge and rising sea levels. Saline intrusion threatens not only drinking water but also urban and agricultural infrastructure.
What can be done to combat salt intrusion?
Salt intrusion is not a future problem, but a reality that requires immediate interventions on multiple levels:
According to the researchers, the combination of engineering solutionsnatural approaches and water management policies it is the only way to protect coastal aquifers and ensure fresh water for future generations.
“Communities with the fewest resources will be most affected by rising seas and climate change,” he says Ben Hamlingtonstudy co-author and climate scientist. “This type of research helps identify solutions and protect those who cannot do it themselves.”
Although the situation is alarming, effective solutions exist and must be implemented as soon as possible. Salt intrusion poses a global threat, but with the right combination of international cooperationlocal interventions and sustainable policies, it is possible to preserve aquifers for decades to come.
