...a study now points to an "almost complete destabilisation" as a consequence of climate change. Should the current actually collapse, this would have dramatic consequences for many regions of the world, not just Europe.

The Atlantic Meridional Overturning Circulation, which includes the Gulf Stream, could be on the verge of collapse. Evidence for this has been found by physicist Niklas Boers, who conducts research at the Potsdam Institute for Climate Impact Research, the Free University of Berlin and the University of Exeter. His study was published mid-week in the journal Nature Climate Change.

Measurements have been showing for some time that the current is weakening. It remains uncertain whether this is already due to climate change — but it does fit with what is expected as global warming increases. This is because freshwater from heavier rainfall and melting Arctic ice is causing the engine of the oceanic conveyor belt to splutter — the belt that transports heat from the Caribbean to higher latitudes.

To put it simply, the engine works like this: some of the warm water evaporates on its journey northward through the Atlantic, which increases the salinity of the remaining water and makes it heavier. It sinks and flows back southward through the deep ocean. Additional freshwater can therefore disrupt this process and weaken the current.

On top of that, the overturning circulation is considered a tipping element. That is to say: beyond a certain point, it might not just weaken in proportion to global warming — it could destabilise abruptly and irreversibly.

That would be a catastrophe. Europe, for example, owes its mild climate to the warm water from the south. In many regions of the Southern Hemisphere, the current shapes the monsoon. A collapse of the overturning circulation would have dramatic and unforeseeable consequences for agriculture and therefore for global food security.

Read more at: klimareporter.de