The Southern Ocean absorbs roughly half of all human-made carbon and 90% of the excess heat from the atmosphere, but scientists cannot reliably predict how that will change as Antarctic sea ice shrinks. This matters because climate models currently lack a realistic picture of what happens under sea ice during winter and spring—the seasons when carbon uptake is most active. Sea ice acts as a physical lid trapping carbon in the ocean, but when it melts, more sunlight reaches the water, boosting the growth of tiny organisms that absorb carbon. Researchers do not know which of these competing effects will dominate as ice continues to decline. The CARB-SEA project will combine numerical models with new observations from the Weddell Sea—where sea ice is expected to shrink fastest—to untangle how physical and biological processes interact under the ice. If successful, the project will produce a roadmap for building more realistic representations of the ocean carbon cycle into the next generation of climate models. This is fundamental science: it will not directly change anyone’s daily life, but it will improve the predictions that governments and industries use to plan for a warming world.
View original technical description
The Southern Ocean plays a major role in absorbing carbon and heat from the atmosphere, storing about half of human-made carbon and 90% of the heat. However, because of its remoteness and hostile environment, it is the least-studied ocean on Earth, especially during winter and spring when many important processes happen. It is particularly hard to study how these processes work when there is sea ice covering the ocean surface. Sea ice around Antarctica has been reducing and will likely keep shrinking due to warming and climate change. It is important to understand how these changes in sea ice affect how much carbon the Southern Ocean will continue to absorb from the atmosphere. Such knowledge is crucial for improving climate models and making better predictions of potential future changes. One of the big questions is how physical processes (like sea ice forming) and biological processes (like organisms using sunlight to grow) interact under the ice and influence the carbon cycle. Sea ice acts like a lid, trapping carbon in the ocean; but when there is less ice, more sunlight can penetrate into the ocean, increasing biological activity and absorbing more carbon from the atmosphere. We still do not know exactly how these two processes will interact together in the future and, as a result, how much carbon the Southern Ocean will be able to absorb if more sea ice melts. To address this, the CARB-SEA project will study how sea ice and light availability affect the carbon cycle under the ice, using numerical models. Our focus will be on the Weddell Sea, where sea ice is expected to decline the most in the coming decades. We will combine numerical models with new observations from the ice-covered Weddell Sea, which will be gathered by our international partners. This will allow us to develop a roadmap for a more realistic representation of the ocean carbon cycle in the next generation of climate models and improve future predictions.
Plain English summaries and category classifications on this site are generated by AI and may not perfectly reflect the original research.
Is something wrong? Let us know