Can the Ocean Store More Carbon Than Previously Believed?

Carbon sink

The oceans can absorb and store large amounts of carbon dioxide (CO2) from the atmosphere. According to a recent study published in the journal “Nature,” the role of the oceans as a carbon sink is likely significantly larger than previously thought, with a potential underestimation of about 20%.

The international team of marine researchers focused on the role of plankton, tiny organisms that absorb carbon dioxide at the sea surface and convert it into organic material through photosynthesis during their growth. When these organisms die, parts of them are broken down into small particles known as “marine snow.” This material is denser than saltwater and, as a result, sinks to the ocean floor, where carbon is stored or serves as a nutrient for various deep-sea organisms.

Utilizing a database containing measurements from research vessels since the 1970s, the seven-member research team created a digital map of the flows of this “marine snow” in the world’s oceans. Based on this data, they estimated the ocean’s storage capacity for carbon dioxide to be 15 gigatons per year, a figure higher than the previous estimate of approximately eleven gigatons according to the 2021 IPCC World Climate Report.

Good news, then—but more for our understanding of the importance of marine ecosystems. This will hardly solve the acute climate problem, according to a statement from the Lemar Marine Research Center in Brest, France, whose biologist Frédéric Le Moigne was involved in the study. The process of absorption takes tens of thousands of years and is by no means sufficient to compensate for the exponential growth of man-made CO2 emissions. If this problem is solved, however, we can count on the power of the oceans to regulate the climate in the long term.