Last summer, Greenland shed 600 billion tons of ice, raising global sea levels by 2.2mm in just two months. Things have been going slightly better on the opposite side of the planet. While west Antarctica has been melting at a faster pace in the last decade, the east side of the continent’s ice mass has been growing steadily. Or, at least, that’s what scientists thought.
Researchers at the University of California Irvine and NASA’s Jet Propulsion Laboratory have recently warned that east Antarctica’s Denman Glacier might be prone to collapse. The glacier is a 12-mile wide stream of ice, lying atop bedrock. According to the paper, the glacier lost 268 billion tons of ice between 1979 and 2017. This is a mere fraction of what happened in Greenland last year, but using radar interferometer data from satellites the scientists found that, because of the ground shape beneath Denman’s western side, there is potential for a quick and irreversible retreat.
Denman Glacier’s western flank flows over the deepest land canyon on Earth, plunging at least 11,000 feet (3,500 metres) below sea level. At the moment, the canyon is mostly cut off from the sea due to the ice piled inside and above it. But, as the glacier edge retreats, warm ocean water will pour into the canyon. ‘That means substantial increases in global sea levels in the future,’ remarked the authors. It is not about millimetres anymore, but rather one-and-a-half metres, or almost five feet. More than enough to start redrawing the geography of several low-laying countries and to bury a few Pacific islands forever.
While the 20.7C recorded in Antarctica last February barely made the news, what should make the world worry is the relentless rise of average polar temperatures, with consequent ice melt. Climatologists never predicted such a rapid warming at the top and the bottom of the planet, where temperature change is felt three or four times more than in London, Dakar or Sydney. Greenland and Antarctica are losing mass six times faster than they were in the 1990s. In 2013, the IPCC projected sea level rise of 52–98cm by the end of the century. Many reckon it is a very conservative prediction.
Being populated by just a few thousand scientists, Antarctica is the only continent you can write about without ever mentioning the word ‘coronavirus’. Yet, in recent years climate change has made South Pole tourism so much easier and cheaper that 78,000 visitors (+40 per cent) were projected for the summer season that just ended. In other words, that immunity record may change too.