Winter is coming to Antarctica, and that may be the only thing that keeps another of its major ice shelves from collapsing. On Tuesday, scientists from the British Antarctic Survey announced that there had been an enormous fracture on the edge of the Wilkins ice shelf, which started breaking last month.
That province of ice, a body of permanent floating ice about the size of Connecticut, lies on the western edge of the Antarctic Peninsula, the part of the continent regarded as most vulnerable to climate change. Scientists flew over the break — itself covering some 160 square miles — and what they saw is remarkable: huge, geometrically fractured slabs of ice and, among them, the rubble of a catastrophic breach. A great swath of the ice shelf is being held in place by a thin band of ice.
What matters isn't just the scale of this breakout. Changes in wind patterns and water temperatures related to global warming have begun to erode the ice sheets of western Antarctica at a faster rate than previously detected, and the total collapse of the Wilkins ice shelf is now within the realm of possibility.
It also comes as a reminder that the warming of Earth's surface is occurring much faster at the poles than it is in more temperate regions. It is easy to think of ice as somehow temporary, but scientists say that the Wilkins ice shelf may have been in place for at least several hundred years.
Nothing dramatizes the urgency of global warming quite like a fracture of this scale. There is nothing to be done about a collapsing polar ice sheet except to witness it. It may be too late to stop the warming decay at the boundaries of Antarctic ice, yet there is everything to be done. Humans can radically change the way they live and do business, knowing that it is the one chance to find a possible limit to radical change in the natural world around us.