Atlantic circulation, which involves the Gulf Stream and thus is often mistakenly called by that name, carries warm water towards the northern and southern polar regions, where it cools down, sinks to deeper levels and returns towards temperate and tropical latitudes. The amount of heat transported in the Atlantic Meridional Overturning Current (AMOC), has a direct impact on the climate along Europe’s Atlantic coasts.

Jochem Marotzke, Max Planck Institute for Meteorology, Hamburg, Germany, and colleagues report the first prediction of the fluctuations in Atlantic circulation. Their prognosis was possible because they were able to check the model’s predictions against real-world measurements. It is extremely costly to acquire such data, which is not currently available for any other ocean outside the Atlantic, and even there is only recorded at one latitude, 26.5 degrees north.

Comparison of the model’s calculations with the real data has shown that the simulation can, so far, generate reliable predictions four years into the future. There will be no changes other than the usual seasonal variations during that time. 

• Max-Planck-Gesellschaft, Munich, Germany