Northern oceans pumped CO2 into the atmosphere

Typography

At the same time the pH of the surface waters in these oceans decreased, making them more acidic. Both of these findings imply changes in ocean circulation and primary productivity as a result of natural climate changes of the time. The findings were recently published in Nature Communications.

Oceans changed function

Today the cold Arctic and Nordic Seas are especially efficient areas for uptake of CO2 from the atmosphere. The oceans have been capable of mitigating some of the increase in greenhouse gas release resulting from human activities such as combustion of fossil fuels, by absorbing about 40% of the emitted CO2

“Our research shows that areas in Norwegian Sea had changed their function on  several occasions through the past 135 000 years: Instead of absorbing CO2 from the air, they released more of the greenhouse gas into it.” says first author of the study Mohamed Ezat from Centre of Arctic Gas Hydrate, Environment and Climate (CAGE), Department of Geosciences at UiT The Arctic University of Norway.

At the same time the pH of the surface waters in these oceans decreased, making them more acidic. Both of these findings imply changes in ocean circulation and primary productivity as a result of natural climate changes of the time. The findings were recently published in Nature Communications.

Oceans changed function

Today the cold Arctic and Nordic Seas are especially efficient areas for uptake of CO2 from the atmosphere. The oceans have been capable of mitigating some of the increase in greenhouse gas release resulting from human activities such as combustion of fossil fuels, by absorbing about 40% of the emitted CO2

“Our research shows that areas in Norwegian Sea had changed their function on  several occasions through the past 135 000 years: Instead of absorbing CO2 from the air, they released more of the greenhouse gas into it.” says first author of the study Mohamed Ezat from Centre of Arctic Gas Hydrate, Environment and Climate (CAGE), Department of Geosciences at UiT The Arctic University of Norway.

First study of its kind from the Nordic Seas

Ice cores from Antarctica show that the amount of atmospheric CO2 varied in pace with the shifting climate of ice ages and interglacial periods of the past. 

“We always thought that oceans played a major role in these shifts, as it is the largest active CO2 reservoir on this time scale. But it has remained unclear how and where in the ocean CO2 was stored and released from”, says Ezat.

Continue reading at Center for Arctic Gas Hydrate, Climate and Environment

Illustration: The illustration identifies the high-latitude North Atlantic as a significant CO2 sink (The purple areas are the most efficient sinks, while red ones are sources of CO2 in the modern ocean). The white star shows the location of the studied sediment core. The map was generated using data of Takahashi et al. (Credits: Mohamed Ezat)