Study Aims to Better Understand Iceberg-Tsunami Dynamics
Iceberg calving can create powerful waves when large chunks of ice fall from glaciers into the ocean. A recent study conducted 66 experiments to better understand the features of iceberg calving to determine iceberg-tsunami strength and parameters.
Crowded Backcountry Ski Slopes Increase Risk of Skiers Endangering Each Other
Avalanche risk is on the rise as more people enter backcountry alpine terrain. A new study seeking to quantify the risk to multi-party avalanches hopes to raise awareness and provoke discussion.
Read the story by Grennan Milliken on GlacierHub here.
Cruikshank Awarded Polar Knowledge Canada’s 2019 Northern Science Award
From the Polar Knowledge Canada press release: “Polar Knowledge Canada is pleased to announce that the recipient of the 2019 Northern Science Award is Dr. Julie Cruikshank. The award was presented at the ArcticNet Annual Scientific Meeting on December 5, 2019, in Halifax, Nova Scotia.
“Dr. Cruikshank, Professor Emerita of Anthropology at the University of British Columbia, has a long and distinguished record of documenting the oral histories and life stories of Athapaskan and Tlingit elders, and exploring Yukon First Nations’ systems of narrative and knowledge. Her work, built on a foundation of respectful relationships, has helped Yukon First Nations recognize and honour the strengths of their cultural traditions, and has brought new insight into the nature of history and the interplay of different knowledge systems. Yukon Indigenous governments regularly draw on Dr. Cruikshank’s work and her knowledge.”
Read the story published by Polar Knowledge Canada here.
Iceberg tsunamis can be dramatic and violent events. A recent paper used large-scale experiments to better understand tsunamis generated by iceberg calving. The team of scientists set up a large tank and used heavy blocks to create waves under controlled conditions. The different iterations of the experiments revealed some of the differences that can be found when icebergs fall into water or rise to the surface in various ways.
The findings were published at the 38th International Association for Hydro-Environmental Engineering and Research World Congress (IAHR 2019) in Panama City. The researchers sought to better understand the different features of iceberg-tsunamis that result when icebergs of different sizes calve. They aimed to expand their research by comparing the new findings to the features of tsunamis caused by landslides. The team hopes that their work will serve to create benchmark test cases that future research can benefit from.
Lead author Valentin Heller, a professor of environmental fluid mechanics at the University of Nottingham, highlighted the work’s immediate and future impacts. “The research enables the efficient systematic prediction of iceberg-tsunamis for a wide range of calving mechanisms for the first time,” Heller told GlacierHub. “In the longer term, this is likely to impact the design of coastal infrastructure and disaster risk assessment in areas where iceberg-tsunamis occur.”
The process through which blocks of ice break off the terminus (end) or margins (sides) of glaciers, ice shelves, or ice sheets and fall into a body of water, typically an ocean, is called iceberg calving. Calving events range from rarer instances in which very large chunks of ice break off, like in the video above, to more frequent events with much smaller pieces of ice separating, like in the video below. Calving events can cause iceberg-tsunamis, examples of which can be seen in both videos.
Though glacier melt is increasing worldwide due to the climate emergency, Heller said an increase in ice loss will not automatically bring about an increase in number or strength of iceberg-tsunamis. This is because other melting mechanisms are playing a role as well. “Ice mass loss is primarily driven by two main components; (i) melting of ice and runoff in the form of water from the ice sheet surface and (ii) discharge through glaciers terminating in the sea in the form of iceberg calving.” He continued, saying that “an acceleration of ice mass loss through (ii) does not necessarily result in larger iceberg-tsunamis.”
Iceberg-tsunamis are dangerous to coastal communities, tourists, and the fishing and shipping industries. Greenland has been the site of multiple significant iceberg-tsunamis; one tsunami at the Eqip Sermia glacier in 2013 produced waves so substantial a tourist boat landing was destroyed. The inhabitants of the village Innaarsuit, located in Greenland, were on high alert in 2018 when a 330-foot tall iceberg drifted into the waters near their homes, bringing with it the threat of flooding.
The research team conducted 66 unique, large-scale experiments in a 50 by 50 meter basin with heavy blocks of up to 187 kilograms each with different variations of iceberg volume, geometry, kinematics, and initial position relative to the water surface. They looked at five iceberg calving mechanisms; capsizing, gravity-dominated fall, buoyancy-dominated fall, gravity-dominated overturning, and buoyancy-dominated overturning. The researchers wrote that “gravity-dominated icebergs essentially fall into the water body whereas buoyancy-dominated icebergs essentially rise to the water surface,” distinguishing the two categories.
The researchers looked at nine parameters influencing iceberg-tsunamis that could impact wave heights and their decay. The parameters monitored were released energy, water depth, iceberg velocity, iceberg thickness, iceberg width, iceberg volume, iceberg density, water density, and gravitational acceleration.
The data showed that tsunami heights caused by gravity-dominated fall and gravity-dominated overturning are approximately an order of magnitude larger than those generated by capsizing, buoyancy-dominated fall, and buoyancy-dominated overturning. In other words, icebergs that fall into the water from above are much more hazardous than icebergs released underwater. Heller told GlacierHub that the researchers were surprised about this large difference because it had not been quantified before.
Diving deeper into the researchers’ analysis reveals that the wave magnitudes generated by the gravity-dominated overturning mechanism created the largest tsunamis, the gravity-dominated fall mechanism created the second largest tsunamis, and the three other mechanisms had waves that were up to a factor of 27 smaller. In other words, the two processes that result from icebergs essentially falling into the water created much larger tsunamis than the mechanisms where icebergs rise to the water surface.
A further difference between the two largest wave producers and the three smaller is that for the gravity-dominated mechanisms the largest wave amplitude was observed earlier in the wave train. For the three processes that resulted in smaller waves, the largest wave amplitude was found in the middle of the wave train.
The results of the study will be useful to both scientists and policy-makers. Heller told GlacierHub that the “results [will] help scientists looking into wave runup at shorelines and wave impact on infrastructures, such as coastal buildings, by providing the necessary offshore wave parameters to support their work.” He elaborated, saying that predicting the heights of iceberg-tsunamis “helps to make decisions on how close to a glacier front ships can safely navigate or if evacuations are necessary, as in the case of the village Innaarsuit on Greenland.”
“Iceberg-tsunamis is a relatively new field of research and people are just starting to realize the significance of such waves for coastal infrastructure, tourists and coastal communities,” Heller said. As the body of research grows, we will have a better understanding of how iceberg-tsunamis function. Once more information is available, impacted communities will be better able to prepare for such events.
This Photo Friday features “The Icebergs,” painted by Frederic Edwin Church in 1861, on permanent display at the Dallas Museum of Art. “The Icebergs” draws on a combination of influences: Church’s real-life observations during his month-long voyage in the North Atlantic Ocean, accounts written by other explorers, and the mysterious, ethereal quality of the Arctic. At a Sotheby’s auction in 1979, the painting sold for $2.5 million, the most any American painting had sold for at public auction at the time.
The Pine Island Glacier (PIG) is losing ice rapidly. During the past 25 years, the ice of the PIG and its neighboring glaciers in west Antarctica’s Pine Island Bay thinned between 3.9 and 5.3 meters a year, accounting for about 5 to 10 percent of observed global mean sea-level rise. Before 2015, however, the front of the PIG had been at a relative standstill since the 1940s, not retreating as one might expect of a melting glacier. Why? To account for this unique situation, a recently published study in The Cryosphere points to ridges below the ice that likely held the PIG’s ice front in place despite its rapid melting.
In August 2015, the long steady front of the PIG changed significantly when large sections of ice broke off during a calving event when the glacier retreated upstream and its orientation shifted. This change presented an exciting opportunity in 2017 for researchers from the Alfred Wagner Institute for Polar and Marine Research to map the seafloor formerly covered by the PIG.
To complete this mapping project, the researchers employed an echo sounder mounted to the hull of the research vessel RV Polarstern, in addition to complementing remote sensing data acquired by satellite. The information acquired by the expedition through echo sounding showed the seafloor features that were present below the PIG. With this data in hand, the researchers had the idea to correlate this information with satellite data from the past to the present to better understand the role of these features for the calving behavior of PIG, according to lead author Jan Erik Arndt, who spoke with GlacierHub about the study.
These survey methods revealed a complex, underwater landscape once covered by the PIG. The discoveries included a 10-kilometer long ridge and two other high points. At its deepest point, Pine Island Bay reaches down over 1,000 meters, while the submarine ridge peaked at 375 meters below the ocean’s surface and the two downstream high points peaked at 350 and 250 meters below the surface
How did these sub-surface features impact the PIG? Satellite data from January 1973 until March 2005 showed a rumple in the PIG’s ice above the location of shallowest section of the underlying ridge. A glacial rumple is similar to a bump on a beach towel that suggests there is a beach toy or pile of sand below it. In the case of the PIG, the ridge below the ice acts as an obstacle in the the way of the ice, leading to a raised section of the glacier directly above the point of contact between it and the ridge. This rumple is not observed after March 2005 in the satellite data, indicating that the ice after this date had thinned to such a degree that it either was no longer in contact with the ridge or was too light to produce a signature on the surface.
The loss of contact with the ridge was consequential. In the time before this separation when the PIG was in contact with the underwater ridge, the ridge acted as a “pinning point,” holding it in place. However, after the ice had thinned considerably, the ridge no longer acted as a restraint on the PIG. As a result, in the time since there was evident contact between the two, four major calving events occurred.
The first of these events took place in 2007 when the PIG advanced and made contact with one of the subsurface downstream high points (A in figure 3). This impact placed what is known as “back stress” on the glacier upstream from the point of contact, causing rifts to form in the ice and ultimately leading to the calving event.
The process leading to the 2011 calving event was similar, the researchers state. In this instance, the second subsurface high point (B in figure 3) trapped a dense cluster of icebergs between it and the PIG ice shelf, placing back stress on the upstream ice leading to the calving event.
The 2015 event was different: The ice-flow velocity of the northern edge of the PIG’s ice shelf was nearly at a stand still, whereas the velocity of the ice shelf’s central and southern edges increased. Further, the direction of the northern edge’s ice flow shifted around 3 degrees clockwise, while the direction of the central and southern edges did not change (C in Figure 3). The reason? The northern edge of the ice-shelf was likely making slight contact with the submarine ridge, according to the authors.
As a result, the calving line that had not changed orientation in decades finally did change due to the loss of contact between the ice and its previous pinning points as well as from melting from below driven by warm ocean waters. The most recent calving event which occured in 2017 happened along the same orientation, which aligns with a new pinning point to the north near Evans Knoll, a small snow-covered hill that rises above sea level. The point near the knoll is likely one of the last anchors acting on the PIG, according to Arndt.
This new calving line and loss of contact with past pinning points could have grave implications for PIG. A 2017 study on the PIG and a number of other glaciers in the area found that changes to a glacier’s ice shelf propagate upstream within just a few years. For the PIG, this likely means the glacier’s flow will speed up and thinning will increase, leading to further melting.
It is unlikely the PIG’s calving line will retreat much further over the next few years thanks to the new pinning point stabilizing the glacier near Evans Knoll. However, the authors note that there is continued thinning due to melting. This thinning has the potential to destabilize the glacier and unfortunately may have already started, according to Arndt. The large icebergs produced by the recent calving events have broken up into smaller icebergs much more quickly due to the thinner ice than events in the past, when they remained stable for longer. This ongoing breakup and subsequent melting of calved icebergs will contribute to already rising global sea-levels, threatening the millions of people who live along the coast. And unlike the ridges that held the front of the PIG for decades, many coastal communities will not have anything to hold back the sea.
From Science: “Some locations on Mars are known to have water ice just below the surface, but how much has remained unclear… The ice sheets extend from just below the surface to a depth of 100 meters or more and appear to contain distinct layers, which could preserve a record of Mars’ past climate. They might even be a useful source of water for future human exploration of the red planet.”
From The Maritime Executive: “The U.S. Coast Guard’s International Ice Patrol said Thursday that 2017 was the fourth ‘extreme’ season in a row for icebergs in the North Atlantic, with 1,008 bergs tallied in the shipping lanes… The count was high due to powerful storms and to the retreat of Greenland’s glaciers, which both contributed to more calving events.”
Check out more information about the migrating icebergs here.
Ice-diving Drones on Risky Mission at Antarctic Glacier
From Scientific American: “This month a fleet of seven underwater robots developed by the University of Washington (U.W.) in Seattle is heading into this world on a risky yearlong mission. Their goal: help forecast sea level rises by observing the melting process in this hidden topsy-turvy world, where layers of warm and cool water mix at the shelf.”
Explore more about the dangers facing the drones and their mission here.
Field study sounds cool: a group of scientists take boats out into untraveled waters on an important scientific mission, even witnessing extraordinary scenery like an iceberg calving event along the journey. However, the breathtaking beauty of such a trip can also come at a price, sometimes even human life!
“I like working in Alaska, but I face the difficulties of any ice or ocean research project,” said Erin Pettit, an associate professor at University of Alaska Fairbanks. Pettit finds it hard to find a reliable boat and captain for her trips, and too much ice in the fjord often limits how close she can get to the glaciers. The risks to her personal safety rise when she has to work on cold or rainy days.
“It can be really dangerous in Alaska, so we send the kayaks out,” said June Marion, the principal engineer for a new study using remote-controlled kayaks to research Le Conte Glacier. The oceanic robotic kayaks are controlled by a laptop a few miles away, according to Marion.
“When the calving event happens and an iceberg falls onto the kayak, we do not need to sacrifice valuable human life,” she said. “More importantly, the kayak can go further into unexplored regions. We are more hopeful to collect data.”
With a radio controller or a computer, the researchers navigate the kayak by clicking on points on a map, sending the kayak directly to the location for study. The engine can even be started using a computer program.
“There are always new technologies being used on glaciers,” said Pettit.
Guillaume Jouvet et al. figured out another way for scientists to avoid danger during field work. They used unmanned aerial vehicles (UAVs), also known as drones, to study calving of the Bowdoin Glacier in Greenland in 2015. They combined satellite images, UAV photogrammetry, and ice flow modeling, drawing important conclusions from the results.
With UAVs, researchers are able to obtain high-resolution orthoimages taken immediately before and after the initiation of a large fracture, including major calving events. In this way, Jouvet et al.’s study demonstrates that UAV photogrammetry and ice flow modeling can be a safer tool to study glaciers.
This technology has also been successfully applied to monitor Himalayan glacier dynamics: the UAVs can be used over high-altitude, debris-covered glaciers, with images of glacier elevation and surface changes derived at very high resolutions, according to W. Immerzeel et al.. UAVs can be further revolutionized to develop current glacier monitoring methods.
Scientists like Marion and Pettit are excited to see these new technologies developed to study glaciers and save lives. They are hoping for more methods to achieve this goal.
Magnificent, beautiful and mysterious, glaciers are a critical part of nature. For thousands years, humans have responded to glaciers through art, incorporating them in paintings, poems, folk songs, and more recently, movies. With the development of modern arts, specifically the film industry, glaciers have popped up in a range of creative endeavors from documentaries to animated pictures.
Explore some popular films featuring glaciers with GlacierHub.
Chasing Ice (2012) is the story of one man’s quest to gather evidence of climate change. A documentary film about environmental photographer James Balog, it tells the story of his trip to the Arctic to capture images to help tell the story of Earth’s changing climate.
The film included scenes from a glacier calving event lasting 75 minutes at Jakobshavn Glacier in Greenland, the longest calving event ever captured on film.
“Battling untested technology in subzero conditions, he comes face to face with his own mortality,” the film introduction states. “It takes years for Balog to see the fruits of his labor. His hauntingly beautiful videos compress years into seconds and capture ancient mountains of ice in motion as they disappear at a breathtaking rate.”
Ice Age (2002) is one of the most popular animations in the world and its sequels have continued to delight thousands of children and adults. First directed by Chris Wedge and produced by Blue Sky Studios, the film is set during the ice age. The characters in the film must migrate due to the coming winters. These animals, including a mammoth family, a sloth Sid, and a saber-tooth tiger Diego, live on glaciers. They find a human baby and set out to return the baby.
The animation won positive reviews and awards, making it a successful film about glaciers.
Jökulsárlón, an unearthly glacial lagoon in Iceland, makes its appearance in several James Bonds films, including A View to Kill (1985) and Die Another Day (2002).
A View to Kill, starring Roger Moore, Christopher Walken and Tanya Roberts, was also filmed on location at other glaciers in Iceland, including Vatnajökull Glacier in Vatnajökull, Austurland, Iceland.
China: Between Clouds and Dreams
The documentary China: Beyond Clouds and Dreams (2016) is an award-winning new series by Director Phil Agland. The five-part series tells intimate human stories of China’s relationship with nature and the environment as the country grapples with the reality of global warming and ecological collapse. See the trailer here.
Commissioned by China Central Television and filmed over three years, the film includes a scene of glaciers on the Tibetan Plateau, where the impacts of climate change are most obvious.
There are numerous harbor seals (Phoca vitulina) living in tidewater glacier fjords in Alaska. Harbor seals are covered with short, stiff, bristle-like hair. They reach five to six feet (1.7-1.9 m) in length and weigh up to 300 pounds (140 kg). Tidewater glaciers calve icebergs into the marine environment, which then serve as pupping and molting habitat for harbor seals in Alaska. Although tidewater glaciers are naturally dynamic, advancing and retreating in response to local climatic and fjord conditions, most of the ice sheets that feed tidewater glaciers in Alaska are thinning. As a result, many of the tidewater glaciers are retreating. Scientists are studying the glacier ice and distribution of harbor seals to understand how future changes in tidewater glaciers may impact the harbor seals. Jamie Womble, a marine ecologist based in Alaska, is one of them.
As Womble put in her recently published paper in PLOS One, “The availability and spatial distribution of glacier ice in the fjords is likely a key environmental variable that influences the abundance and distribution of selected marine mammals; however, the amount of ice and the fine-scale characteristics of ice in fjords have not been systematically quantified. Given the predicted changes in glacier habitat, there is a need for the development of methods that could be broadly applied to quantify changes in available ice habitat in tidewater glacier fjords.”
To conduct her research, Womble has used a variety of analytical tools including geospatial modeling (GIS), multivariate statistics, and animal movement models to integrate behavioral and diet data with remotely-sensed oceanographic data. Most recently, she has worked with object-based image analysis (OBIA).
“OBIA is a powerful image classification tool. Many people studying forests and urban areas use it,” Anupma Prakash, a colleague of Womble and professor of geophysics at the University of Alaska, told GlacierHub. “In our case, we could not use the satellite images because the satellite images did not have the details we required. We flew our aircraft quite low so we saw a lot of detail and could identify individual icebergs.”
OBIA offers an enhanced ability to quantify the morphological properties of habitat. Satellite imagery, on the other hand, is not a viable method in Alaska as there are few cloud free days.
“We wanted to classify our images into water, iceberg, and brash-ice (small pieces of ice and water all smushed together),” Prakash added. “The color and smoothness of water helped us isolate it. For icebergs the color, shape, and angular nature helped us isolate it, and the rest was bash-ice.” So it is now feasible to quantify fine-scale features of habitats in order to understand the relationships between wildlife and the habitats they use.
Thanks to the work of scientists like Womble and Prakash, OBIA can now be applied to quantify changes in available ice habitat in tidewater glacier fjords. The method can also introduced in other geographic areas, according to professor Prakash. Now that there is a more advanced method to study the harbor seals in Alaska, the hope is that other researchers will use the OBIA method to make further discoveries about key ocean habitats.
Researchers recently reported that a threatened species of Arctic seagull had made a colony in an unusual place— on an offshore iceberg. This is the first report of these gulls breeding on an iceberg.
They reported in a short note published in the journal Polar Biology that ivory gulls, Pagophila eburnea, had formed a breeding colony of around 60 adults with numerous chicks and fledglings among them. The gulls, which are named for their all-white plumage, may have made their home there because it allows them to avoid predators (including the Arctic fox, wolf, and polar bear) and because it is close to an area of open water that is a rich source of food. The find represents a new place to look during counts of such birds.
The iceberg was covered with gravel and debris, and after analysis, the researchers reported that the likely source was a glacier moraine in Greenland. The iceberg was located nearby the North East Water polynya in Northeast Greenland. (A polynya is an area of open water where sea ice would normally be found. These zones open up seasonally, and are rich in foods that the gulls and other predators can consume, including small fish and krill.) The distance from feeding zones to nesting areas can be up to 100 km each way, so having the iceberg near the feeding area saves energy for the parents.
The colony was spotted serendipitously while the researchers were taking observations from the deck of the RV Polarstern on August 9, 2014. The scientists were looking for seabirds and marine mammals as part of a long-term study of the relationship between predator densities and environmental factors in the polar region.
Ivory gulls typically breed on nunataks, which are areas of exposed rock from mountain ice and snow fields, or on remote coastal islands. It had been suspected that the gulls might breed on offshore ice islands. A few studies also document the birds breeding on gravel-covered sea ice, though these were near the shore.
The iceberg that was home to the colony was 70 km offshore. The researchers state that they assumed the iceberg was grounded, rather than freefloating, based on the typical depth of East Greenland icebergs.
The observation of these gulls is also interesting because they are a near-threatened species, according to the IUCN Red List. While the ivory gull was among the most frequently seen gull in the Arctic in the 1990s, it is not even among the top ten any more, according to the researchers. The estimated total number of individuals of this species in the Greenland sea has also fallen, according to observations by the authors. The global population of these gulls is now estimated at between 19,000 and 27,000, they noted. The number of gulls seen in this colony makes it an average sized colony for this species. The authors weren’t able to provide an estimate of the number of young gulls, because they blend into the gravel so well and because the authors weren’t able to observe all parts of the breeding site closely.
The authors wrote, “Juveniles of different age (from chicks in downy plumage to ﬂedglings) were observed, but not quantiﬁed because parts of the breeding site could not be sighted properly at close range and due to their excellent camouﬂage on the gravel.”
The ivory gull does not venture far from the Arctic Ocean, according to the Cornell Laboratory of Ornithology, and the iceberg was located in the Greenland Sea, which is nearby. Earlier this year, an ivory gull was spotted in Duluth, Minnesota which, though close to the border between the US and Canada, is still far from its normal range. The appearance of the gull attracted bird enthusiasts from all over the country who saw it as a once-in-a-lifetime opportunity to add a species to their life lists.
As climate change has resulted in more icebergs calving off Greenland, it will be interesting to see whether birds like the ivory gull will be able to use them as breeding sites, or if other colonies of ivory gulls are found on icebergs in the future.
Iceberg Ahead! A New Study Finds Way to Avert Disaster
“When performing offshore operations in the Arctic, there are several challenges. One of those challenges is the threat of icebergs on offshore structures and vessels. Icebergs can exert extremely high loads on vessels, offshore platforms, and seabed installations.”
Find out how the team is proposing safer Arctic travels.
Glaciers Retreat Toxic Metals Are on the Move in Tibet
“In mountain ecosystems, the most important natural source of trace metals is from the weathering of parent materials. However, in recent decades, the metals in mountain regions are mainly from anthropogenic sources including mining, refinement, and fuel combustion. Considering the toxicity of trace metals, it is necessary to investigate and evaluate their mobility and eco-risk in mountain ecosystems.”
Learn more about the possibly toxic soil exposed as glaciers retreat.
With Red and Green Snow, Algae Just Misses Christmas Season
“We demonstrate that green and red snow clearly vary in their physico-chemical environment, their microbial community composition and their metabolic profiles. For the algae this likely reflects both different stages of their life cycles and their adaptation strategies. ”
Read more about the colorful algae and what it means for soil quality.
“Iceberg calving is ultimately related to the mechanical failure of ice. However, predicting mass loss from calving events remains challenging because calving takes on diferent forms under different conditions. For example, large tabular icebergs sporadically detach from freely foating ice tongues with many years of quiescence between major calving events”
Read more on ESRI’s Story Maps and Time-lapse here.
Linking Earth’s Ice Ages to Ocean Floor topography
“The evidence comes from seafloor spreading centers: sites throughout the ocean where plates of ocean crust move apart and magma erupts in between, building new crust onto the plates’ trailing edges. Parallel to these spreading centers are “abyssal hills”: long, 100-meter-high ridges on the diverging plates, separated by valleys. On bathymetric maps of seafloor topography, they look like grooves on a record. These grooves, it now turns out, play the tune of Earth’s ice ages.”
“As glaciers increasingly melt in the wake of climate change, it is not only the landscape that is affected. Thawing glaciers also release many industrial pollutants stored in the ice into the environment. Now, within the scope of a Swiss National Science Foundation project, researchers from the Paul Scherrer Institute (PSI), Empa, ETH Zurich and the University of Berne have measured the concentrations of a class of these pollutants – polychlorinated biphenyls (PCB) – in the ice of an Alpine glacier accurately for the first time.”
Iceberg Calving is Extremely Sensitive to Climate Change
“Sea level rise is among the greatest threats due to climate change. Over the next century, ice sheets and glaciers will be one of the main contributors, through melting and calving of ice into the oceans. The amount of calved ice is not easy to reproduce in computer simulations, and due to the rapid and non-linear variability of calving fluxes, they are usually difficult to include in models forced by evolving climatic variables. Simulation of iceberg calving remains one of the grand challenges in preparing for future climate change.”
“I started from a data analysis conducted by the Swiss Glacier Monitoring Network to see the map of the glacier and its relative changement in the length variation from 1961 and 2011. It’s interesting the word used to call the part of a glacier that goes under a certain mass. They are called “dead”. All the pictures shown here are taken to the new entrance of the glacier, in the “dead” part of it. Looking at the map, 50 years ago, this would have been completely covered by the ice.”