A recent oceanographic study detected a 30% drop in salinity in one of the saltiest regions of the Atlantic Ocean. This chemical change, unprecedented in modern records, triggers new climate alarms.
The phenomenon is linked to the accelerated melting of glaciers and the increase in precipitation in high latitudes. As a result, large volumes of freshwater are entering the North Atlantic.
Consequently, the Atlantic Meridional Overturning Circulation (AMOC) is compromised, a system that includes the Gulf Stream. Both function as a thermal conveyor belt that redistributes heat across the planet.
How does thermohaline circulation work and why is it crucial?
The stability of this system depends on thermohaline circulation, that is, the delicate balance between temperature and salinity. Under normal conditions, the cold, salty water of the North Atlantic sinks due to its higher density.
This sinking allows warm tropical waters to rise northward. Thanks to this process, Western Europe maintains a milder climate than other regions at the same latitude.
However, as salinity decreases, the surface water becomes less dense. Thus, a layer forms that prevents sinking and weakens the oceanic engine.
This pattern is not an isolated event but an indicator of a possible “tipping point.” Current models suggest that the collapse could occur sooner than previous forecasts.
How does this phenomenon impact the environment?
If the AMOC weakens critically, the global climate would undergo a profound reorganization. Europe could face drops of up to 10°C in a few decades.
At the same time, the southern hemisphere would retain more heat, intensifying droughts and tropical monsoons. This would affect agricultural production and global food security.
Moreover, the sea level would not rise uniformly. On the east coast of the United States, cities like New York, Boston, and Miami could experience accelerated flooding.
As the current that redistributes water masses slows down, the ocean would tend to accumulate in certain coastal areas. Added to this is the thermal expansion of warmer, stagnant water.
Signs of a system losing resilience
The year 2025 is shaping up to be one of the hottest on record, reinforcing the context of global warming. The massive influx of freshwater shows that the Arctic is releasing more ice than the Atlantic can absorb.
Consequently, the 30% desalination acts as a symptom of a system under extreme stress. Once the critical threshold is surpassed, there is no technology capable of restarting ocean circulation.
Therefore, scientific monitoring and drastic emission reductions become priorities. Avoiding the collapse of the AMOC means preserving an essential component of the planetary climate balance.
