For more than a century, the Southern Ocean, the huge ocean that surrounds Antarctica, has been quietly helping protect the planet: it has absorbed a lot of the carbon dioxide (CO₂) and heat produced by humans when we burn coal, oil, and gas. Thanks to this, global warming has been slower than expected.
However, a new study by German scientists warn that, when humanity finally stops using fossil fuels and the Earth starts cooling, the Southern Ocean could release much of that trapped heat back into the air.
This release would act like a big “burp” of heat that could cause another wave of global warming, lasting for about a hundred years. So, let’s find out more about this, shall we?
How the Southern Ocean helps our planet
The Southern Ocean has an important function on the Earth’s climate. It’s like a giant sponge that absorbs the CO₂ and the heat from the atmosphere, which has avoided the planet to heat so fast as it was expected due to pollution caused by humans.
However, this sponge has its limit. Scientists explain that, when we stop emitting greenhouse gases, the Southern Ocean coils start to release that heat and make the planet heat again (even without new human emissions).
What scientists discovered
This discovery was made by a group of researchers from the GEOMAR Helmholtz Centre for Ocean Research in Germany, led by Dr. Ivy Frenger.They used complex climate models to study how the planet might change over time. These models include information about air temperature, ocean movement, sea ice, and CO₂ levels. Here’s the scenario they studied:
Humans keep burning fossil fuels for about 70 more years.
CO₂ levels in the air become twice as high as they were before the industrial age.
Then, humans suddenly stop releasing CO₂ — maybe because of new technology or strong global action.
For the next several hundred years, we start to remove CO₂ from the air, and the Earth begins to cool down slowly.
This seems like great news, right? But, actually, the models show something very worrying: even though the air gets cool, the oceans will still keep heat in their deep waters.
What does the ocean ‘’burps’’ heat?
During global warming, the Southern Ocean has accumulated heat in its deep waters. Before industrialization, this ocean lost part of the heat in a natural way, thanks to a process called upwelling. In this process the cold and deep water rises to the surface, but with the temperatures increasing this process has been reduced and the ocean has started to keep more and more heat.
When humans stop emitting CO₂ and the planet cools, the Southern Ocean won’t be still. With the passage of time, it will release part of the heat kept like a huge burp coming from the deep waters.
Scientists discovered this phenomenon could heat the atmosphere again, even without human emissions, and that this new warming would last more than 100 years! What’s more, the warming rhythm would be similar to the one we have experienced in the last century.
Most affected parts of the world
This new r¡warming won’t affect the same way everywhere. According to the study, the effect will be stronger in the South Hemisphere, which means places like South America, Africa, Australia, and many southern islands. These regions are already more vulnerable to climate change, so they could suffer more serious consequences.
What we can learn
The message from this study is clear: we need to act sooner to reduce CO₂ emissions, so the amount of stored heat is smaller and the future “burp” is weaker. The planet’s oceans have long memories and what they remember from our pollution today might come back to affect the climate in the future.