Flying over Antarctica, it’s hard to see what all the fuss is about. Like a gigantic wedding cake, the frosting of snow on top of the world’s largest ice sheet looks smooth and unblemished, beautiful and perfectly white. Little swirls of snow dunes cover the surface.
But as you approach the edge of the ice sheet, a sense of tremendous underlying power emerges. Cracks appear in the surface, sometimes organized like a washboard, and sometimes a complete chaos of spires and ridges, revealing the pale blue crystalline heart of the ice below.
As the plane flies lower, the scale of these breaks steadily grows. These are not just cracks, but canyons large enough to swallow a jetliner, or spires the size of monuments. Cliffs and tears, rips in the white blanket emerge, indicating a force that can toss city blocks of ice around like so many wrecked cars in a pileup. It’s a twisted, torn, wrenched landscape. A sense of movement also emerges, in a way that no ice-free part of the Earth can convey – the entire landscape is in motion, and seemingly not very happy about it.
Broken ice where Thwaites Glacier heads out to sea.
Ted Scambos
Antarctica is a continent comprising several large islands, one of them the size of Australia, all buried under a 10,000-foot-thick layer of ice. The ice holds enough fresh water to raise sea level by nearly 200 feet.
Its glaciers have always been in motion, but beneath the ice, changes are taking place that are having profound effects on the future of the ice sheet – and on the future of coastal communities around the world.
Breaking, thinning, melting, collapsing
Antarctica is where I work. As a polar scientist I’ve visited most areas of the ice sheet in more than 20 trips to the continent, bringing sensors and weather stations, trekking across glaciers, or measuring the speed, thickness and structure of the ice.
Currently, I’m the U.S. coordinating scientist for a major international research effort on Antarctica’s riskiest glacier – more on that in a moment. I have gingerly crossed crevasses, trodden carefully on hard blue windswept ice, and driven for days over the most monotonous landscape you can imagine.
Mountains direct the flow of glaciers toward the sea.
66 North via Unsplash
For most of the past few centuries, the ice sheet has been stable, as far as polar science can tell. Our ability to track how much ice flows out each year, and how much snow falls on top, extends back just a handful of decades, but what we see is an ice sheet that was nearly in balance as recently as the 1980s.
Early on, changes in the ice happened slowly. Icebergs would break away, but the ice was replaced by new outflow. Total snowfall had not changed much in centuries – this we knew from looking at ice cores – and in general the flow of ice and the elevation of the ice sheet seemed so constant that a main goal of early ice…