A modelling study shows how heat stored in the ocean could be released after centuries of global cooling.
A modelling study shows how heat stored in the ocean could be released after centuries of global cooling.
So far, the ocean has helped to buffer global warming by absorbing more than 90 per cent of the excess heat trapped in the Earth system by the anthropogenic greenhouse effect. A new modelling study by the GEOMAR Helmholtz Centre for Ocean Research Kiel has now examined how the ocean might respond if atmospheric carbon dioxide was drastically reduced in the future. The results show that, after centuries of cooling, the Southern Ocean could trigger renewed warming by releasing the stored heat back into the atmosphere. Whether this would occur as a single major “heat burp”, in many smaller pulses, or continuously over centuries remains unclear. The study has now been published in AGU Advances.
Human emissions have pushed the Earth into an energy imbalance, the effects of which are most clearly felt in the ocean. Since the start of the Industrial Revolution, the ocean has absorbed more than 90 per cent of the surplus heat that could no longer be radiated into space. Consequently, the ocean has significantly mitigated atmospheric warming.
“The ocean is an extraordinarily large heat reservoir, and until now it has helped to soften the warming of the atmosphere,” says Dr Ivy Frenger, lead investigator of the ERC Starting Grant project OSTIA (The Ocean’s Role in Mitigating Climate Change) at GEOMAR. In a new modelling study, Dr Frenger and her team investigated how the ocean would respond if society managed to stop emitting greenhouse gases, subsequently cooling global temperatures by removing CO2 from the atmosphere. Their findings suggest that, after centuries of cooling, heat accumulated in the deep Southern Ocean could be released in the form of a “burp”, warming the atmosphere again.
Read More: Helmholtz Centre for Ocean Research Kiel (GEOMAR)
Image: The Southern Ocean surrounding Antarctica plays a key role in the Earth's climate system. It connects all ocean basins and acts as a kind of ‘release valve’ where heat stored deep in the ocean can eventually escape. (Credit:
Photo: Martin Visbeck, GEOMAR)
