The oceans play a crucial role in absorbing carbon dioxide (CO2) and regulating the climate, a role yet to be fully understood. However, the oceans’ ability to contribute to climate regulation may decline and may even be reversed in the future. The oceans that are now the blue lungs of our planet could end up contributing to global warming.

It presents a synthesis of the state of knowledge about the oceans’ role in the carbon cycle and points to the way ahead. Its objective is to provide decision-makers with the knowledge needed to develop climate change mitigation and adaptation policies for the coming decade.

The report highlights the role of the oceans since the industrial revolution as a sink for the carbon generated from human activity.

Indeed, without ocean and land sinks, atmospheric CO2 levels would be close to 600 ppm (parts per million), 50 percent higher than the 410 ppm recorded in 2019, which is already well above the agreed target of limiting global warming to two degrees Celsius.

The UNESCO insisted that there is a danger that this process will be reversed. Instead of absorbing carbon, the oceans could contribute to the warming greenhouse effect of CO2 emissions.

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