The Southern Ocean is acidifying at such a rate because of rising carbon dioxide emissions that large regions may be inhospitable for key organisms in the food chain to survive as soon as 2030, new US research has found.

Tiny pteropods, snail-like creatures that play an important role in the food web, will lose their ability to form shells as oceans absorb more of the CO2 from the atmosphere, a process already observed over short periods in areas close to the Antarctic coast.

Ocean acidification is often dubbed the "evil twin" of climate change. As CO2 levels rise, more of it is absorbed by seawater, resulting in a lower pH level and reduced carbonate ion concentration. Marine organisms with skeletons and shells then struggle to develop and maintain their structures.

Using 10 Earth system models and applying a high-emissions scenario, the researchers found the relatively acidic Southern Ocean quickly becomes unsuited for shell-forming creatures such as pteropods, according to a paper published Tuesday in Nature Climate Change.