Seas rising by 6.5 metres threatening London, New York, Tokyo. This is the future that awaits us if we do not stop the melting of the ice in Antarctica.
An image of Antarctica's ice in full melt and an unambiguous phrase, Point of no return. This is how the cover of the latest issue of Nature presents itself — one of the oldest and most prestigious scientific journals in the world — calling into question the future not only of the Antarctic ecosystem, but also of cities such as London, Mumbai, New York, Shanghai as we know them. This scenario is raised by a study conducted by the Potsdam Institute for Climate Impact Research, together with the University of Potsdam, Columbia University in New York and Stockholm University.
More than half of the planet's freshwater reserves are held by the Antarctic ice sheet, which is around five kilometres thick, explains Ricarda Winkelmann, co-author of the research, in a statement released by the Potsdam Institute for Climate Impact Research. Greenhouse gas emissions from human activities are, however, causing temperatures in the atmosphere and in ocean waters to rise. The ice covering the South Pole is thus losing mass and becoming increasingly unstable, raising sea levels across the entire planet.
Scientists have developed a series of projections based on different scenarios. If global warming remains at 2 degrees centigrade above pre-industrial levels, seas will rise by 2.5 metres. If it reaches 4 degrees centigrade, they will rise by 6.5 metres. If it even breaks through 6 degrees for a sufficient period of time, the (catastrophic) projection is a rise of nearly 12 metres. London, Mumbai, New York and Shanghai are just some of the cities that could suffer severe damage. And these estimates take into account only Antarctica's contribution.
Antarctic ice has existed for 34 million years, but the melting process it is now undergoing is irreversible: not even a new drop in average global temperatures would be enough to restore it to its original state. In this sense, the only glimmer of hope would be a return to the temperatures that characterised the pre-industrial age. But scientists state plainly that this is "extremely unlikely" to happen.
"It is the burning of coal and oil that causes current and future greenhouse gas emissions and, consequently, determines whether and when critical temperature thresholds in Antarctica will be crossed," Winkelmann notes. "And even though the disappearance of the ice takes place over a very long timeframe, the CO2 levels that bring it about could be reached in the near future. We can now decide whether we will be able to stop global warming. The fate of Antarctica is truly in our hands — and with it the fate of our cities and our cultural sites around the world, from Copacabana beach in Rio de Janeiro to the Sydney Opera House." "If we abandon the Paris Agreement," she concludes, "we abandon Hamburg, Tokyo and New York."
