We’re finally getting close-up, fearsome views of the doomsday glacier
RAM!The bright red hull is the US Coast Guard icebreakerGlacierThe ship crashed onto the ice. The impact shook every rivet on the ship, which measured 95 meters long. It was 1985 and the researchers were sailing through Antarctica’s Amundsen Sea. Jill Singer, a graduate student, was able to break ice during the voyage. She explains, “You push the throttle up or thrusters up.” It would lift the front of your car.GlacierOut of the water enough to drop on the ice and smash it.”RAM!After several days of charging at sea-ice with a bone-aching resolve, theGlacierThey broke through.
“[We] “broke into… a beautifully tranquil, ice-free ocean, the eye in an hurricane of ice,” Terry Hughes, glaciologist, later wrote about the moment–one that he had been imagining since the 1970s, when he began to worry about glacial collapse.
TheGlacierThe first ship to sail into Pine Island Bay.
The Intergovernmental Panel on Climate Change predicts that sea levels will rise.By 2100, it is almost half a meter. This water will move several million people from coastlines all over the globe. Pine Island Bay will receive a large portion of the water. It will be primarily from Thwaites, one the planet’s largest glaciers and roughly as large as Great Britain.
Glaciers are formed when snow is consolidated into ice over hundreds and years. The ice below begins to flow like a river as the weight of the new snow and ice decreases. Thwaites is an outlet ice glacier. It flows all the way to sea level. Its coast edge is 120 km long and is surrounded by a white wall of ice, which rises to 40m above the ocean’s surface. It also reaches more than 200 meters deep.
Thwaites and Pine Island Glacier, its neighbor, drain around one-third the West Antarctic Ice Sheet – the ice sheet that extends west from the natural dividing line between the Transantarctic Mountains. These glaciers are forming icebergs faster than new ice can ever be made. They contribute five percent to annual sea level rise, which is roughly 0.18 millimeters per year. This is equivalent to dumping more than 20 million Olympic-sized swimming pool into the ocean each and every year. Thwaites’ location and shape mean that the rest of West Antarctic Ice Sheet could be affected by its collapse. That’s enough water for three meters of sea level rise, which would redraw coastlines and transform the planet we know.
Hughes and other researchers have raised concerns about the glaciers flowing into Pine Island Bay, Amundsen Sea embayment, for almost 50 years. However, international coordination of research in the region has only started in 2018, with the creation of theInternational Thwaites Glacier Collaboration. The potential collapse of Thwaites Glacier poses one of the greatest environmental threats to global civilisation today, and we have barely begun to understand why. Why did it take us so long to understand?
Pine Island Bay is, as it turns out to be, one of the most difficult places in the world. The story of Thwaites’ discovery is also a tale of the triumphs and challenges of science at the bottom of this planet.
Pine Island Bay is a small bay off the coast of West Antarctica. It flows into the Amundsen Sea, a stormy and ice-choked area of Antarctica that no country has claimed. It is remote even for Antarctica. The nearest permanently occupied research station to it is 1,500 km away.
Captain James Cook was the commander of the first ship to reach Amundsen Sea. Captain James Cook and his crew aboard the HMS Arctic were able to reach the Amundsen Sea in January 1773.ResolutionThey were the first to cross the Antarctic Circle (the invisible line of latitude at the 66deg south). Cook was sent south by the British government in order to determine if land existed below Australia. This region has been a longstanding curiosity for members of the Royal Society, England’s most prestigious scientific institution. One year later, theResolutionCook described the Antarctic Circle as “an immence Icefield… so close packed together, that nothing could enter it.” Cook again crossed it but was stopped short by the “immence Icefield” (S 71deg10′ W 106deg54’). Legend has it that George Vancouver, a young midshipman, climbed up to the bowsprit to wave his hat above the icy waters. He declared himself the southernmost person in history. Cook’s was named after the coordinates of the ship.ne plus ultraLatin for “no more than that.”
Cook returned to the beginning.ResolutionIt was less than 300 km north of Thwaites glacier. Although it is a short distance, Cook’s ne plus super in the region was not broken even though a modern edition Cook’s journals was published in 1971. Cook was the only person to have sailed further south into Amundsen Sea in 200 years.
Pine Island Bay was not seen by sea but by air for the first time. The US Navy organized Operation Highjump in the 1940s. This involved sending aircraft carriers to map different areas of the Antarctic coast. The USSPine IslandPine Island Sound in Florida gave the name to the ship, which was named after it. But thePine IslandPine Island Bay was never reached. Instead, the aircraft returned with the first aerial view of the embayment.
The harsh conditions of Amundsen Sea were not an incentive for many, so the US Navy and Coast Guard shifted their attention to other Antarctic regions in the decades that followed. Pine Island Bay was the last unmapped area of coastal land below the Antarctic Circle in 1980.
Hughes began to ask questions about the region around that time. Hughes, a glaciologist who called himself a cowboy scientist, was outspoken and had a talent for making dramatic statements that could distract science. He was also a respected theorist, whose papers were filled with mathematical equations that predicted the behavior of glacial water under different conditions.
Hughes was interested in two issues that were not well-studied at the time: a warming planet, and the possible collapse of the West Antarctic Ice Sheet. Hughes was involved in a major project that aimed to reconstruct the growth and fall of ice sheets during the last Ice Age. His attention was drawn to Pine Island Bay, a coastal area where the outer edges of glaciers might calve into icebergs or break apart with extraordinary speed. Hughes noticed in satellite images that there was a surprisingly short glacial shelf. Why didn’t the glacial shelf extend all the way across the bay. Outlet glaciers usually flow into an “ice shelf”, a floating area of ice that extends above the water. This floating shelf can be used to protect “grounded” inland glaciers that are directly on bedrock. David Glacier, an East Antarctica glacier of similar size, flows 100 km above the ocean. Pine Island Glacier’s floating Ice, however, is half as long.
Scientists knew that the planet was warming but many believed Antarctica was still safe. Simply put, Antarctica was too cold to fail. Hughes wasn’t so sure. Hughes was not so sure. He thought that the absence of a large floating island ice shelf in Pine Island Bay could indicate instability among nearby glaciers, which reach deep within the heart of West Antarctic Ice Sheet. He called Pine Island and Thwaites Glaciers, in 1981, the “weak underneath” of West Antarctica: glaciers that could weaken and trigger the collapse of the West Antarctic Ice Sheet. He meant catastrophic. The oceans could rise more than a meter in a single human lifetime. Hughes’s research paper “Deluge II and The Confederacy of Doom” was titled with the bombastic title that raised eyebrows among his colleagues.
Hughes was an unofficial guest onboard the ship when he passed Cook’s ne ultra and entered Pine Island Bay, 1985. Yet he hoped to learn more about Pine Island Glacier–particularly, whether it was flowing too fast to be stable. He was unable to collect any useful data due to the bad ice and wind conditions in this bay.
The National Science Foundation (NSF) funded the research cruise. However, curiosity was not enough to justify the expense of driving ice day and nights on taxpayer’s money. Hughes claimed that if there was a glaciological fire in Pine Island Bay, NSF should see it. Hughes had not found it.
Hughes’s theories were actually questioned by early satellite data. NASA and the US Geological Survey launched the first Earth Resources Technology Satellite (now known as Landsat) in 1972, fresh from the space race. “Remote sensing has revolutionized glaciology,” says glaciologist Karen Alley. “It wasn’t that long ago that nobody had a picture the entire continent,” she says, referring to Antarctica. “And now, we have continent-wide flow velocity and ice thickness.”
Studies based on Landsat satellite imagery in the 1980s and 1990s suggested that Pine Island Glacier was not just stable but actually stable.GainingIce: One estimate says that there are 50 gigatonnes per year. It was getting bigger to match its nickname, The PIG. Thwaites Glacier, an afterthought in these studies, was apparently also growing.
It appeared that Pine Island Bay should not be considered an area of concern. Hughes was not convinced. Hughes was still skeptical about the lack of floating ice shelves in the bay. He was unable to find any data to support his theories.
How could studies using Landsat go wrong? Alley says that Landsat doesn’t do a lot. Landsat is a specialist in data capture at the surface. However, Hughes discovered that the critical information he needed was hidden beneath the glaciers. Landsat couldn’t reach it. A new type of satellite technology was about turn glaciology upside down.
The European Space Agency launched the first European Remote Sensing Satellite in 1991. It was equipped with instruments for radar interferometry, a new technique. Eric Rignot, a University of California glaciologist, saw the potential of the technique, especially after seeing it used on a NASA spacecraft a few years later.
Rignot was able, using radar interferometry to locate facts about the glaciers that were previously invisible. He could see the deformations in ice up to one millimeter. He could read the ice movement hourly, not just year to year. He could also locate the grounding line.
The grounding line is where glaciers lift from the rock and begin to float above the ocean. It’s also where the ocean water gnaws at the glacier’s base, causing it to slip away from its bedrock. Most of the ice in West Antarctica is well below sea level.,In a marine basin that is bowl-shaped. Warmer ocean water can flow downhill to this bowl, melting the frozen at the grounding line and causing the ice to move inland. The floating ice doesn’t alter sea level because it melts. Instead, it is already displaces ocean water like ice cubes in water. Once-grounded ice will melt if the grounding line recedes. This is what it looks likeDoesIncrease sea level and destabilize the glacier: the glacier is thinned from below and then breaks down more easily. The wall of submerged glaciers that covers Thwaites’ marine basin is over 1,000m deep. This gives the water a large surface area. The water can push the grounding line quickly inland, but it will slow down if it comes into contact with elevated bedrock, such as an underwater ridge or mountain that “pins”, the ice. Thwaites Glacier is home to one such pinning spot, located approximately 40 kilometers from the current grounding line. This pinning point exerts pressure on the glacier’s interior like a flying buttress pressing against a cathedral wall. The glacier could pour its ice faster if the ice shelf is removed from the pinning point.
Researchers cannot tell how fast the grounding line retreats if they don’t know where it is. Rignot was able to calculate melt rates that were orders of magnitude higher than any other time. He calculated that Greenland’s major glacier was melting at a rate of up to 20m per year. (Previous data had indicated that even the most fragile glaciers melt about 10 to 20 cm per year. Rignot knew that the figures would be wild for many of his colleagues. “Woah! He thought maybe his data was bad, but the evidence is mounting up that these melt rate are much higher.” He received pushback throughout 1990s. Many were skeptical that glaciers could disappear so quickly. What could possibly cause a glacier to disappear so quickly?
The unexpected source provided the answer. Stanley Jacobs, an oceanographer at Columbia University in New York City, believed that the ocean might be involved. He was familiar with Hughes’s work, and had published a 1991 paper calling for “icebreaker penetration” and “detailed oceanographic sampling” in the “largely unknown” Amundsen Sea. He wanted to return a ship to Pine Island Bay.
Although the ocean’s importance is obvious now, researchers at the time were more concerned with flow velocity than what happened when the glacier reached it. Rignot states that few people in glaciology believed the ocean could be important: “It wasn’t on the horizon.”
It is notoriously difficult for oceanographers to study. Even in the best conditions, it can be dangerous and expensive. Rignot was so impressed by the quality of satellite data that he worked mostly from his California office. Satellites were not enough for ocean data. Satellites can only give temperatures at the surface; ice melt and subzero winds make it very cold in polar water. They can’t reach deeper warm waters.
Rignot states, “To get data from the ocean, you must go there.” Jacobs did exactly that in 1994.
Since the voyage of the Pioneer, no one has broken through the ice around Pine Island Bay.Glaciera decade earlier. Adrian Jenkins, an oceanographer, recalls that Jacobs was going into uncharted waters. “No one knew the edge of continental shelf, it was mismapped.
The cruise began in the Ross Sea, south-west of New Zealand. The team discovered extremely cold ocean water, at -2.2 degrees Celsius, which is well below the freezing point for fresh water. They noticed a change as they continued to Pine Island Bay. They reached Sulzberger Bay just around the corner of the Ross Sea and found water at 0 degrees Celsius.
As they neared their goal, the water became even warmer. Jenkins recalls, “We managed to get our ship into Pine Island Bay. This was clearly the place I wanted to get,” “And the observations changed us thinking about the region.” Jenkins was inspired by the warm temperatures and learned MATLAB, a scientific software that allows for rough estimations. “I found these really high melting rates, like 100m per year–I thought too high.WayJenkins recalls that the price was too high. Jenkins recalls, “I believed there must have been something wrong. I spent the next ten years trying to find out what.” It turns out that it isn’t as high an overestimate than I thought.
The team initially had difficulty publishing their results. The team submitted a paper to a major publication, but it was rejected without an outside review. It was deemed not sufficiently important.
Rignot was a key ally. Although his work was primarily on Greenland and Hughes’s obsession with Pine Island Bay, he knew about Hughes’s unique obsession. He was fascinated by Jenkins’s high melt rate, which was similar to the figures Rignot had discovered in Greenland. The whole picture was made possible by the warm water discovered in Pine Island Bay by Jacobs and Jenkins.
Rignot recalls that he had heard about the instability of West Antarctica. He began to examine radar interferometry data from Pine Island Glacier’s grounding point, and he “…”Boom!It was flashing on the screen. It was a big event.” It took him almost two years to publish his calculations. He says, “I wanted to be damn sure that what was I seeing was real.” “Because it was real, that would be very significant.”
Rignot presented findings at a 1997 conference that Pine Island Glacier’s grounding lines were retreating by approximately 1.2 kilometers each year.
Jenkins comments, “This is where Eric’s work set alight the world.” Jenkins, Jacobs and their colleagues had demonstrated that glaciers were melting more quickly than previously thought due to the warm ocean. Melting can still be a stable process, and is not always a problem. The danger comes when the grounding line recedes, allowing warm ocean water greater access to the interior. These cases may result in the glacier not melting slowly like an ice cube, but it could collapse like a cathedral.
Rignot’s calculations are valid today: Researchers believe Pine Island Glacier’s groundingline retreated by approximately one kilometer per annum in the 20 years prior to 2011, although it seems to have slowed recently. Thwaites continues to retreat at a rate of around one kilometer per year and loses approximately 37 gigatonnes annually. This is enough to cover the entire contiguous United States five meters deep in ice each year. Hughes began to look into Pine Island Bay in 1980. He may not have fully understood the mechanisms but he was right.
It’s like driving an icebreaker. But, changing the direction of Antarctic research would be like driving an icebreaker. It’s slow and costly. NSF took six years to return a ship to Pine Island Bay after the 1994 cruise. The ice was so thick that Jacobs couldn’t even get to Pine Island Glacier on the first attempt in 2000. Jenkins and he continued to publish with Rignot in an effort to prove that warm water was quickly shifting the grounding line.
Their ship finally broke through in 2009. It had been 15 years ago that anyone had ever sailed these waters. They now had cutting-edge technology: Autosub3, an automated underwater drone. Autosub3 confirmed Jacobs’s suspicions that the ocean was responsible. A deep band of warm, or Circumpolar Deep water, was reaching under the glacial shelf. It had already ate a huge cavity under Pine Island Glacier.
These developments at the bottom of our planet prompted the next generation of polar researchers. David Holland, a Canadian mathematician who was interested in modeling ocean-water interactions, was on the second plane that landed atop Pine Island Glacier. He was well aware that ocean currents respond to wind patterns and had built a sophisticated weather station to track the atmospheric changes. He and two of his assistants camped on Pine Island Glacier for five summers straight before shifting their attention to Thwaites.
He explained that they were still trying to figure out where to focus their research. Holland’s team began at Pine Island, building on previous work. He says that while they were there, Holland’s team thought, “Shouldn’t it be next door at Thwaites?”
It is difficult to study because of the storms that surround Thwaites. A joint project between the United States of America and the United Kingdom included the first systematic airborne survey below Thwaites. It revealed patterns of ice flow into Thwaites’ interior and its connection with the surrounding ice sheets. It was becoming apparent that the impact of this project could have a significant impact.
Thwaites is much larger than Pine Island Glacier, and it’s a lot more. It has a long front, more than 120 km. The base slopes steeply to almost 1,000 meters below the sea level. These dimensions provide warm ocean water with a lot of ice. Thwaites’s catchment area, which is the ice that flows into glacier, measures approximately 700 kilometers. This is the distance between Boston, Massachusetts and Washington, DC. It’s the perfect candidate to collapse on a large scale. Thwaites contributes to sea level rise by four times more than Pine Island Glacier.
Pine Island Glacier has been the focal point for decades. Both glaciers are neighbours, but on an Antarctic scale with over 50 km of thick sea ice between most accessible ice fronts. It’s possible that Thwaites was not seen from shipboard, as earlier cruises were so determined to reach Pine Island Glacier. Holland discovered that the glacier is deteriorating, making it more difficult to reach.
December 2021 headlines stated that the Thwaites Ice Shelf might “shatter like car windscreens” in five years. It’s difficult to know for certain. WeDoThe floating ice shelf acts as a buttress and keeps Thwaites’s inland, ground ice stable. We also know that the ice shelf is fracturing into enormous numbers of icebergs. Runaway melting can occur if the ocean pushes the grounding line too far.
Thwaites is the cork in the bottle for West Antarctica. Because of its size and central location, it could cause a ripple effect across the entire West Antarctic Ice Sheet. This could have happened around 125,000 years ago when sea levels were six to nine metres higher than they are today. West Antarctica will not collapse overnight. It could take several hundred years. It might take a few hundred years, but if it does, as many researchers fear, it will redraw the global coastlines.
Holland views the planet using a simple principle: “Play with the atmosphere, expect changes.”
Unusually warm ocean currents are melting ice. These currents are driven primarily by shifting wind patterns. Stronger winds push water from the surface, allowing water that is deeper and warmer to rise up to the ocean basin below the glaciers. Changes in air temperature are what the winds respond to. These changes are caused by greenhouse gas emission.
Holland says that the winds will change the ocean and the ocean will melt Antarctica. This is Holland’s summary. There is evidence that changes in the atmosphere can raise sea levels by several metres within a century. The systems are so complex that it’s difficult to predict. Holland says that we have apps on our phones to predict the weather tomorrow but not for the ocean and ice sheets. The Intergovernmental Panel on Climate Change states that sea level rise projections require a prediction of the “dynamic contribution” to ice sheets.
Science is a human, imperfect, and communal process. It moves slowly through self-correction, weaving its way through uncertainties like an iceberg amongst icebergs. Precision is essential in Pine Island Bay, where ocean charts are still being updated. Precision takes time.Thwaites’s time seems less with each new study.
This article appeared first inHakai Magazine,This article is republished here with permission.