There’s no more awe-inspiring sight than an iceberg, large or small, drifting in polar waters—not to me, anyway. For a day and a half, I watched this one in the Ross Sea tower near the ship maybe 1/2 a mile long, creating its own weather, eroding as waves crashed against it, and drawing huge numbers of sea birds to feed in the rich waters icebergs create around them.
Icebergs are born—or calved—from the melting margins of ice sheets. Most Antarctic icebergs drift counterclockwise around Antarctica, gradually melting to the east of the Antarctic Peninsula as they reach the warmer waters of the Antarctic Circumpolar Current (ACC), which races almost unimpeded around this vast continent. (In fact, this is where I’ll be from March to May next year—an area known as Iceberg Alley.)
When an Iceberg Melts
When an iceberg melts—even an enormous iceberg such as the Delaware-sized berg that calved from Antarctica’s Larsen C ice shelf in July last year—it doesn’t raise the sea level. Just like ice in your glass or sea ice, icebergs and ice shelves (the sheets of ice upon the ocean and attached to the land) float, displacing the water around them.
But ice shelves have a vital role in retaining or “buttressing” the glaciers behind them. In other words, they act like a wall to hold back the glacial ice flowing toward the sea.
So, when an ice shelf thins, weakens, or disintegrates, its ability to hold back the grounded/land ice behind it diminishes and can fail. And when glacial ice melts, it does raise the sea level. (This is a good time for you to stop and watch this video, an extreme, spectacular, and terrifying example of a rapid collapse from the documentary Chasing Ice.)
Melting Rate has Tripled
Our polar ice, both in the Arctic and the Antarctic, is melting at greater rates. Arctic sea ice is in decline, and the Greenland ice sheet is losing mass. (Note: sea ice forms when sea water freezes. Repeat: melting sea ice does not raise sea level.) Similar processes are underway in the Antarctic, which contains enough land ice that, were the Antarctic Ice sheet to melt completely, global sea levels would rise by around 58 meters (190 feet).
The findings in a recent paper Mass Balance of the Antarctic Ice Sheet from 1992 to 2017, by the IMBIE team published in the journal Nature show that the loss of ice mass in Antarctica has tripled since 1992. Even more troubling is that almost half of that ice loss has been over the past five years. This melting and mass loss is particularly obvious in West Antarctica. Warmer ocean currents are melting ice shelves from below, and other processes are acting upon them; they are weakening, retreating, and accelerating their march to the sea.
Ice loss from West Antarctica has increased from 53 to 159 billion metric tons a year between 1992 and 2017. In fact, the Thwaites Glacier is of such concern that the US National Science Foundation and UK Natural Environment Research Council have teamed up in a massive multi-disciplinary project to study the glacier and the processes affecting it.
These are the subjects that draw me ever onward in my passion for our polar ice, and which took me to the WAIS Workshop, an annual international meeting of glaciologists and other polar researchers, last week. We met from Sunday to Wednesday in Stony Point, New York before moving on to a combined meeting with the International Thwaites Glacier Collaboration at Lamont-Doherty Earth Observatory.
It’s easy to imagine that ice science would be simple; after all, it’s just frozen water, right? But ice and the processes affecting it are surprisingly complex. There are ocean currents to consider, atmospheric conditions, the effect of melt-water, the profile of the ocean floor beneath the ice shelf, seismic activity below it, and of course, the nature of the various forms of frozen water itself, and so much more.
It was thoroughly impressive to see the number and variety of disciplines and methods represented at the workshop. Antarctica is remote, inhospitable (meaning a relatively short summer field season), and vast. Often, scientists must rely on satellite and radar data. What is clear is that collaboration between disciplines is a must, as well as the obvious and clear importance of studying the paleoclimate (what happened in the past) to better understand what’s happening now and may happen in the future. I also thoroughly enjoyed chatting about best ways to talk about it to the public. (I’ve seen a handful of really notable Public Outreach efforts among this crew, too, which I love.) And my amazing, hard-working collaborator Kev and I got to show an animation we whipped up just for the WAIS folks!
Three things stick with me most after WAIS. One is the sheer complexity of polar ice and the immensity of the task to study and understand it.
The second is the incredible spirit of cooperation, collaboration, combined purpose, and the energy of these scientists to tackle it. It gives me great hope and inspiration for my work.
The third is personal. In part, I’m thrilled that one creative collaboration (so far) has come out of the meeting. Mostly, I relish the happiness that came with sitting around a bonfire or picnic table, having a beer, a chat, and a laugh with a bunch of polar researchers.
Perhaps it’s hard for people who live and breathe polar ice to understand how it is to be in a place where I can talk about it, learn so much, get ridiculously excited, and just hang out with people who understand—without explanation—why I care so much, and even some who (like me) get a little choked up when they talk about it. That is a remarkable thing.