By Kate Goldstone
Antarctica, which has long been thought to be relatively safe from vast ice melts, has proved us wrong. It’s actually in just as much trouble as the Arctic.
Plenty of people believed the ice on Antarctica wouldn’t melt as fast as the Arctic. Then, in April 2017, scientists claimed Antarctica’s ice might actually be melting a lot faster than anyone predicted. It matters because Antarctica is home to 90% of the world’s ice. If it keeps melting this quickly, and the continent’s massive ice sheets go, we’re looking at profound worldwide effects including mass flooding.
What’s going on, and is the trend continuing? Here’s what you need to know.
How Arctic and Antarctic sea ice differ
Because the Arctic and Antarctics’ geography is different, so is their ice. The Arctic ocean is partly enclosed, mostly surrounded by land. Its ice is less mobile and floes tend to clump together into thick ridges. Ridge ice has a longer life cycle and stays frozen for longer. The region is home to 5.8 million square miles of sea ice in winter, reducing to roughly 2.7 million square miles by the end of the summer.
The Antarctic is totally different. Made up of land surrounded by ocean, the sea ice there moves freely and drifts faster. There are fewer ice ridges as a result, and the lack of a land boundary to the north means the ice naturally floats northwards into warmer waters before melting. Winter sees about 6.9 million square miles of Antarctic ocean covered in sea ice, but by the end of the summer there are only around 1.1 million square miles of it left.
Clear warnings in 2017
April 2017 saw the first reports of Antarctica’s ice melting faster than previously predicted, thanks to the discovery of a network of lakes and streams under the continent’s ice shelves which created a destabilising influence on the ice above. The study was published in the journal Nature and revealed the process is taking place in areas where scientists didn’t think there was any liquid water. As global temperatures keep rising, the speed of the damage can only increase. The team examined satellite images dating as far back as 1973 as well as aerial images snapped by military aircraft way back in the 1940s. And the results were a shocker – some of the streams flowed for 75 miles, and some of the lakes were several miles across.
A few months later in November 2017 a study examined the east Antarctic Totten ice shelf, finding it unexpectedly vulnerable to warming waters. And still governments failed to react, never mind act. March 2018 saw scientists announce more of the Totten Ice Shelf was floating than they’d predicted. Multiple different types of supporting evidence proved the point. Now it looks a lot like a certainty. If Larsen C and Totten melt, the world’s sea levels will rise as much as 5 metres. Totten could easily contribute a 3m sea level rise all on its own.
Another equally clear warning in 2018
In August 2018, more headline news surfaced about Antarctica’s ice. It appeared a couple of enormous glaciers to the east of the region had lost ice mass disturbingly quickly in the years since the millennium. The results hinted that forecasts for sea level rise this century will have to be revised upwards, but nobody knows exactly how much. While it’s obvious the ice in Antarctica is melting frighteningly quickly, the complex dependencies and inter-dependencies that make it happen aren’t at all clear.
So far most molten Antarctic ice has come from the west of the continent. The Antarctic Peninsula is under particular threat, reaching out into the ocean and exposed to warmer waters, and the Larsen C ice sheet, which famously cracked in 2017, is also to the west. East Antarctica has long been thought to be more stable, cut off from the planet’s weather systems by powerful spinning gales that stop the warmth getting anywhere near. On the other hand it’s so remote that scientists have spent decades guestimating what might happen instead of actually measuring. But they keep getting it wrong. In 2015 one piece of research hinted the region was putting on extra ice, not losing it, but closer examination revealed it was simply not true.
Even if Totten disappears, we probably won’t see a 5m rise by 2100. There’s such a lot we don’t know about the behaviour of Antarctic ice and the many factors a big melt depends on. It apparently takes hundreds of gigatonnes of ice to raise sea levels by just one millimetre, and Totten isn’t anywhere near that level… yet. But it might speed up, and we have no idea how fast the melting could ultimately become once we pass a tipping point, also unknown.
There are more unknowns around the effect of the geology underneath the continent, the shape of the bedrock itself. And the channels running from underneath the Totten link it to the ocean give warmer water the access it needs to potentially kick off a runaway melt.
Only one thing is clear. The original consensus was far too cautious. Now we know for sure Antarctica is losing ice mass hand over fist. It has been losing ice for years. And nobody knows where the tipping point is.
The effects of runaway sea level rises
The cities under the most threat from rising sea levels also happen to be amongst the biggest on the planet, the most financially, socially and culturally important. Alexandria in Africa, The Hague in Europe, Miami in North America and Rio de janiero in South America are all at risk, home to a total of 10 million people, almost all of whom would be displaced. Ten million migrants from just four cities… that’s hard to deal with. And it’s only the tip of the iceberg, if you’ll forgive the pun. On every continent, in every sea-facing country, we’d have to build vast amounts of new housing stock for migrants.
Cities don’t operate in isolation, either. Every drowned city means drowned transport networks, communications networks, power, utilities and food networks, all left under water permanently. Wildlife will suffer just as badly, forced out of natural habitats. It actually doesn’t bear thinking about… but it’s happening all the same. As UN environment chief Erik Solheim said before last year’s Bon conference, “[We] still find ourselves in a situation where we are not doing nearly enough to save hundreds of millions of people from a miserable future.”
What are governments doing about Antarctic ice loss?
Antarctic ice melt is driven by climate change. Governments are not doing enough about climate change. All over the world those in power are still prevaricating, delaying, discussing and disagreeing while Rome burns. It’s our job to force them to act. Will you join us?