Deep ocean warming to increase by 0.2°C in the next 50 years

Scientists say deep ocean warming will increase by 0.2°C, as they find excess heat from the subtropical North Atlantic – at depths of 700m

The oceans currently absorb around 90% of the warming caused by humans.

Research shows that around 62% of overall global warming from 1850-2018 is being held in our deep oceans.

The consequences of a 0.2°C increase over 50 years

Undertaken by a team from the University of Exeter, this research is suggesting that the deep ocean will warm a further 0.2°C n the next 50 years.

The dangers of ocean warming are numerous, with major consequences being rising sea-level, changing ecosystems, currents and chemistry and deoxygenation.

Published in Communications Earth & Environment, Dr Marie-José Messias, from the University of Exeter said: “As our planet warms, it’s vital to understand how the excess heat taken up by the ocean is redistributed in the ocean interior all the way from the surface to the bottom, and it is important to take into account the deep ocean to assess the growth of Earth’s ‘energy imbalance.

“As well as finding that the deep ocean is holding much of this excess heat, our research shows how ocean currents redistribute heat to different regions […] a key driver of warming in the North Atlantic.”

As well as finding that the deep ocean is holding much of this excess heat, our research shows how ocean currents redistribute heat to different regions […] a key driver of warming in the North Atlantic

The team have been studying the system of currents known as the Atlantic Meridional Overturning Circulation (AMOC). The AMOC works like a conveyer belt, carrying warm water from the tropics north – where colder, dense water sinks into the deep ocean and spreads slowly south.

The importance of recognising patterns in the ocean

The team’s research highlights the importance of warming transferring by AMOC, from one region to another.

Dr Messias emphasised that excess heat from Southern Hemisphere oceans is becoming important in the North Atlantic – now accounting for about a quarter of excess heat. Understanding the factors that contribute to this warming will allow future research to tackle these problems at the source.