A new study shows that most of the "excess heat" stored in the subtropical region of the North Atlantic is in the deep sea (less than 700 meters). The ocean absorbs about 90% of human induced warming. The new study found that in the subtropical North Atlantic (25 ° n), 62% of the warming between 1850 and 2018 occurred in the deep sea.
Researchers from the University of Exeter and the University of Brest estimate that the deep sea will heat up further by 0.2 ° C in the next 50 years.
Ocean warming has a range of consequences, including sea-level rise, ecosystem changes, ocean currents and chemicals, and deoxidation.
Dr Marie Jos é Messias wrote: "As the earth warms, it is crucial to understand how excess heat is redistributed by the ocean from the interior to the surface, and also to take into account the deep sea to assess the growth of the earth's energy imbalance. Our study not only found that the deep sea stores a large amount of excess heat, but also shows how ocean currents redistribute heat to different regions. We found that this redistribution is a key driver of warming in the North Atlantic 。”
The researchers studied the current system of the Atlantic meridional overturned circulation (AMOC).
AMOC works like a conveyor belt, transporting warm water from the northern tropics - where colder, denser water sinks into the deep sea and slowly spreads south.
The results emphasize the importance of AMOC in the regional transfer of global warming.
Dr Messias said that excess heat from the southern hemisphere's oceans is becoming more and more important in the North Atlantic - now accounts for about a quarter of the excess heat.
It is reported that the study used temperature records and chemical "tracers" - the composition of compounds that can be used to detect past changes in the ocean.