Extending from the surface to the ocean floor, the ACC transports more water than any other ocean current. It pulls in waters from the Atlantic, Pacific, and Indian Oceans, helping drive a global circulation system known as the conveyor belt, which transports heat around the planet. Cold, dense water that sinks to the ocean floor off Antarctica also helps store carbon in the deep ocean. In both those ways, the Southern Ocean has a crucial impact on Earth’s climate.
Scientists are currently studying how human-driven climate change is altering the Southern Ocean. Ocean water moving through the ACC is warming, scientists have learned, but it’s unclear how much this is impacting Antarctica. Some of the most rapid melting of the continents ice sheets and shelves have been where the ACC is closest to land.
An environment like no other
For now, by fencing in the frigid southern waters, the ACC helps keep Antarctica cold and the Southern Ocean ecologically distinct. Thousands of species live there and nowhere else.
The Southern Ocean “encompasses unique and fragile marine ecosystems that are home to wonderful marine life such as whales, penguins, and seals,” notes National Geographic Explorer in Residence Enric Sala.
What’s more, the Southern Ocean has ecological effects elsewhere as well. Humpback whales, for example, feed on krill off Antarctica and migrate far north to winter in very different ecosystems off South and Central America. Some seabirds migrate in and out too.
By drawing attention to the Southern Ocean, the National Geographic Society hopes to promote its conservation.
The impacts of industrial fishing on species like krill and Patagonian toothfish (which is marketed as Chilean sea bass) has been a concern in the Southern Ocean for decades. In 1982, catch limits were imposed in the region. The largest marine protected area (MPA) in the world was established in the Ross Sea off West Antarctica in 2016. A number of organisations are working to set aside more MPAs to protect the Southern Ocean’s most critical feeding grounds, for example off the Antarctic Peninsula.
“Many nations across the world support the protection of some of these areas from industrial fishing,” Sala says.
Mapping the world as it is
Since the late 1970s, the National Geographic Society has employed a geographer who oversees changes and tweaks to every map that’s published. Tait has been on the job since 2016.
He says he takes a journalist’s approach to the process. It involves staying on top of current events and monitoring who controls what areas of the world.
“It is important to note it’s a map policy, not a policy about Nat Geo’s position on [geopolitical] disputes,” he says. For example, National Geographic maps show that the U.K. controls the Falkland Islands, even though Argentina claims them too. In disputed areas, Tait works with a team of geographers and editors to determine what most accurately represents a given region.
Minor changes happen on a weekly or biweekly basis. Major changes, like labelling the Southern Ocean, are more rare.
Generally, National Geographic has followed the International Hydrographic Organization (IHO) on marine names. While not directly responsible for determining them, the IHO works with the United Nations Group of Experts on Geographical Names to standardise names on an international scale. The IHO recognised the Southern Ocean in its 1937 guidelines but repealed that designation in 1953, citing controversy. It has deliberated on the matter since, but has yet to receive full agreement from its members to reinstate the Southern Ocean.
The U.S. Board on Geographic Names, however, has used the name since 1999. And in February of this year, NOAA officially recognised the Southern Ocean as distinct.
Tait says National Geographic’s new policy will have an impact on how children using maps in school learn to see the world.
“I think one of the biggest impacts is through education,” he says. “Students learn information about the ocean world through what oceans you’re studying. If you don’t include the Southern Ocean then you don’t learn the specifics of it and how important it is.”
The National Geographic Society, committed to illuminating and protecting the wonder of our world, funds Explorers Sylvia Earle, Enric Sala and Seth Sykora-Bodie. Learn more about the Society’s support of ocean Explorers.