The wild waters of the Southern Ocean surrounding Antarctica are one of the planet’s biggest carbon stores. The ocean absorbs around 12% of all carbon dioxide generated by humans each year, but despite its huge importance in regulating the Earth’s climate, it has barely been studied by science.
French explorer and environmentalist Jean-Louis Etienne has spent the last 10 years designing a scientific vessel capable of braving the terrifying waves and winds found there.
His floating laboratory, called the Polar Pod, will stand 100 meters high and weigh 1,000 tons. The structure will be towed horizontally from the east coast of South Africa to the powerful current surrounding Antarctica. It will then “flip” vertically by filling 150-ton seawater ballast tanks, a feature inspired by the US oceanographic platform FLIP.
The vessel has no engine and will be driven by the Antarctic Circumpolar Current, drifting at about 1 knot per hour. The top of the structure – 20 meters above the water – is where the crew will live, sleep and work. The submerged portion keeps it steady. “It is 80 meters below sea level, fixed in very calm water – that’s why it’s very stable,” Etienne tells CNN.
Listening to the ocean
The plan is to “orbit” Antarctica twice in three years and collect data on how humans have impacted the Southern Ocean, explains Etienne. While the main focus will be on measuring the ocean’s capacity to absorb carbon dioxide (CO2), the Polar Pod will be equipped with sensors to measure acidity and wave dynamics, among other things.
“This very large area of cold water all around Antarctica is the largest ocean carbon sink of the planet,” he says – but we don’t know how its ability to absorb carbon dioxide changes throughout the year. “The stability of the Polar Pod will allow the scientists to get this information.”
As the structure will be silent, it will be able to use hydrophones – underwater microphones – to record the “acoustic signature” characteristic of different sea creatures, from krill to whales, and perform a census of marine life, explains Etienne. He also plans for the vessel to help calibrate satellites for NASA and the European Space Agency.
Six wind generators will power the sensors and on-board laboratory, and data will be transmitted to researchers in real-time. The team also plans to transmit live broadcasts and lectures from the Polar Pod.
There will be eight people on board at any given time – four sailors tasked with navigating (and deploying sails to avoid icebergs), three scientists, and a cook. Every two months a ship will bring supplies, a new crew, and sometimes Etienne himself. The doctor and explorer, now 74, has undertaken numerous expeditions to remote polar regions. He hauled a sled on a solo overland trip to the North Pole in 1986 and crossed the Arctic Ocean in a hot-air balloon in 2010.
Construction of the Polar Pod has not yet begun but will be funded by the French government. French oceanographic institution Ifremer will put the contract to build the vessel out to tender.
Etienne is in the process of raising funds for a three-year expedition he hopes will begin in 2024. He says he is not able to disclose costs or how much money has been raised to date.
In good company
The Polar Pod will not be the only structure floating in the Southern Ocean. Over the last six years the Southern Ocean Carbon and Climate Observations and Modeling project (SOCCOM) has deployed 200 robotic floats with advanced sensors to measure oxygen, sunlight, chlorophyll, nitrate and acidity.
The floats look like gas canisters and function a bit like drifting submarines. They have a parking depth of 1,000 meters, and drop to 2,000 meters every 10 days to make a full profile up to the surface and beam the data to scientists.
Prior to the SOCCOM project, the Southern Ocean was “nearly undiscovered” with just a few ship tracks across it, oceanographer and climate scientist Joellen Russell, of the University of Arizona, tells CNN.
“One out of eight molecules of CO2 that is added to the atmosphere is absorbed by the ocean around Antarctica, the Southern Ocean, within a year,” says Russell. “This is the ocean to study. This is the critical component of our Earth’s climate system.”
Russell adds that the Southern Ocean has not been better studied because it’s far away and “catastrophically” dangerous.
While the robotic floats are dotted across the Southern Ocean, mooring a vessel is challenging in the Antarctic Circumpolar Current. “Every time the oceanographic community has deployed a mooring in the ACC it’s been damaged or ripped away in the winter,” explains Russell.
Understanding an important carbon sink
The Polar Pod has a significant role to play in adding to our understanding of how much CO2 is in the ocean, explains ocean biogeochemist Peter Landschützer, of the Max Planck Institute for Meteorology in Germany.
“We know that the Southern Ocean is very important for our climate … we also want to understand how it changes in time as the climate changes,” he says. “We have on the one hand one of the most important carbon sinks, on the other hand, we have very little measures to observe it.”
Other ocean research vessels have have journeyed around Antarctica. In August 2019, an unmanned boat called a Saildrone completed the first autonomous circumnavigation of the Southern Ocean. Despite a run-in with an iceberg that destroyed some of its sensors, the Saildrone was able to collect oceanic and atmospheric carbon dioxide measurements.
The team behind it says it plans to deploy a fleet of Saildrones to measure the exchange of carbon dioxide between ocean and atmosphere in the Antarctic Circumpolar Current.
According to Landschützer, the Polar Pod will be able to provide a more detailed circumpolar view of the carbon cycle because it has both a seawater CO2 sensor and an eddy flux system – a specialized instrument to measure how much CO2 and heat is being transferred between the atmosphere and the ocean.
Landschützer says measuring the ocean-atmosphere CO2 exchange both directly and indirectly is a huge benefit. “I don’t know any expedition [circumnavigating the Southern Ocean] that does that.”
Russell agrees: “I’m delighted, because those flux measurements from inside the Antarctic Circumpolar Current are absolutely essential,” she says. “We don’t have these measurements.”
However, she worries that the vessel may not be sturdy enough to face the hostile conditions, particularly in the winter, pointing out that help will be days or weeks away if it encounters any setbacks.
“The Pod is going to be in literally the fiercest weather on planet Earth,” she says. “I imagine that we’re going to see something we’ve never seen before, and have people and video as well as measurements of the extraordinary change. I just wish they had more mobility, just in case.”
Landschützer says that a better understanding of the Southern Ocean will help to monitor the success of Paris Agreement international climate goals.
He adds that it’s encouraging to see such innovative ideas to tackle the unique problems posed by this ocean.
“The Southern Ocean brings the best out of a scientist because of the challenges,” he says. “You can’t do it the way we’ve always done it, so we have to come up with something new if we want to understand it.”
As well as providing vital data, Etienne says the mission is an eye-catching way to draw attention to the devastating impact of global warming in the polar region.
“We’ll be the teacher from the classroom far, far away,” he says.