Tag: geo and climate

For a week, an iceberg as colossal as it is fragile held everyone in suspense. It arrived like a gargantuan beast that you hope won’t notice you, at the fishing village of Innaarsuit, Greenland, about five hundred miles north of the Arctic Circle. The iceberg posed a mortal threat to the village population of about a hundred and seventy people.

Standing three hundred feet tall (the height of the Statue of Liberty) and weighing an estimated ten million metric tons (equal to thirty Empire State buildings), it’s riven with cracks and holes. If a big enough part of it sloughed off, in a process known as “calving,” it would cause a tsunami, immediately destroying the little settlement on whose shore it rested.

“You don’t want to be anywhere near the water when it’s happening,” a glaciologist who does research in Greenland said. “It’s just incredibly violent.” People began to evacuate.

Innaarsuit residents are a hardy bunch, living in the sort of climatic extremes that temperate zoners might call otherwordly. For much of the summer, the sun is always up. This year, it won’t set again until in early August. The temperature on Friday was thirty-nine degrees Fahrenheit—about as warm as it ever gets—and in the darkness of February and March, the average remains below zero.

There are no trees. People hunt narwhals (polar unicorns), whales, and seals. The single road dead-ends at a cemetery. Boat captains (the only people who can get you off the island, apart from helicopter pilots) are constantly navigating an endless parade of baby icebergs, set loose from their mothers, drifting with the current past the village, often close enough to touch. They tend to be the size of a beach ball, a dinghy, a shack.

The most recent visitor is different, obviously. “This iceberg is the biggest we have seen,” a village council member named Susanne K. Eliassen said. Karl Petersen, the village council chair, called on the press, asking the world for assistance if the berg were to calve. For the crowd watching online, it was like “Jaws.” We hoped desperately that the great white thing would just continue on its way.

Big icebergs are nothing new, but they usually remain far offshore. Ocean currents and wind push the icebergs along, sometimes five or more miles a day. In this case, the berg got stuck in the shallow waters of the bay. Eric Rignot, a glaciologist from the University of California, Irvine, said that it probably originated from one of the nearby glaciers that flow down the fjords along Greenland’s west coast.

Those glaciers have long been notable for pushing a lot of icebergs out into the sea. But nowadays they are in retreat—more ice is more rapidly breaking from the glacier’s face than snow is accumulating on its back. With climate change, what happened in Innaarsuit, Rignot said, is expected to occur more frequently. Joshua Willis, a glaciologist from NASA’s Jet Propulsion Lab, put it in simple terms:

“As things continue to warm up, more ice is gonna come off and float around.” Drought-stricken South Africa wants to tow one such berg to Cape Town, to prevent the country’s taps from running dry.

Drought and torrid heat waves are scorching Europe, too. In England, the land is so dry that archaeologists are discovering new ruins (they hold underground moisture differently than undisturbed land, changing the way crops grow). In Ireland, a five-thousand-year-old henge came into view. Mostly, however, the news is bad.

Sweden is burning as far north as the Arctic Circle, causing evacuations; last week, it was Norway. Wildfires have even broke out in Northwest England, near Manchester. Great clouds of smoke, visible from space—from wildfires in Siberia (there was an unusually bad wave in May) and in the far north of North America, in boreal and subalpine forests and even out on the tundra—blow over Greenland and stay for a while.

The soot and ash blacken the island’s ice sheet and hasten its melting, leading to more tragedy. Last summer, there was a tsunami in a village near Innaarsuit, called Nuugaatsiaq. Thawing permafrost provoked a landslide so massive that it caused a three-hundred-foot wave, one of the largest ever recorded on camera. Four people died, eleven buildings were washed away, and dozens were injured. For the people of Innaarsuit, the danger posed by their stranded iceberg was reinforced by the recent memory of that disaster.

Coincidentally, or not, a few days before the iceberg showed up in Innaarsuit, on July 9th, Denise Holland, a glaciologist from New York University, released a video of what is almost certainly the largest glacial calving event ever recorded on camera. Holland and her husband, David, a scientist who works with her at N.Y.U., and who also studies ice at the poles, were camping at the Helheim glacier, on Greenland’s east coast, in fiberglass igloos they built themselves.

By chance, after twenty years of returning to the same spot to collect data, their camera happened to be on and filming when the calving event began. It lasted thirty minutes. All together, the ice that fell was as big as half of Manhattan, and weighed roughly ten gigatons, making it a thousand times larger than Innaarsuit’s iceberg. “I was speechless, you can’t believe you are seeing something like that,” David told me.

“There are very few photographs or videos of this actually happening,” Willis, from NASA, said. (Holland does research with him at NASA, too.) “They are happening a lot, but they are hard to catch. This only lasted thirty minutes. It’s weeks or months before something like that would happen again.” Although that glacier is located about sixteen hundred miles from Innaarsuit, Holland said it is a typical case of how the village’s berg was born.

It’s also an invaluable document for studying how ice sheets fall apart, to project future sea-level rise. “Ice is a material that we don’t fully understand,” Holland said. Greenland, a field site much easier and cheaper to get to, also acts as a proxy for studying the West Antarctic Ice Sheet—the most vulnerable of Earth’s three major ice sheets, and the biggest polar threat to civilization.

Many scientists believe that the WAIS has started to retreat irretrievably, but no one has a clear picture of how or how quickly it will break apart. One possible theory is that calving could go into overdrive, and the ice sheet’s dissolution could happen catastrophically fast. The evidence is piling up. A Nature study published in June found that, roughly ten thousand years ago, West Antarctica retreated a hundred and thirty-five thousand square miles, when the planet was significantly cooler than it is today.

In another study, published in the previous issue of Nature, researchers found that, from 1992 until 2017, Antarctica had lost three billion tons of ice, and that the annual rate of loss due to melting from the WAIS increased from fifty-three billion tons to a hundred and fifty-nine billion tons. On July 12, 2017, an ice shelf (akin to a dam that slows a glacier’s flow into the ocean) named Larsen C collapsed, launching an iceberg the size of Delaware (ten times as big as the one that the Hollands recorded in Greenland) into the Weddell Sea.

As the ice shelves that border West Antarctica crumble, the glaciers behind them hasten their retreat. The quantity of ice is unfathomably greater than what Greenland holds, capable of raising global sea level by roughly ten feet, and, Willis said, “it’s kind of poised on a precipice.”

Back in Innaarsuit, the great white iceberg remained mostly intact and, with some help from a new-moon tide and benevolent winds, continued drifting north. By Wednesday, everybody felt safe enough to go home. The store opened, the fishermen got back in their boats and resumed catching green halibut. It’s nice when a story about an iceberg has a happy ending, at least for now.

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