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By Lucas Jackson and Elizabeth Culliford
(Reuters) – A loud noise rocked climate scientist David Holland just before going to sleep in his bear-resistant fiberglass dome, installed near a frozen fjord in Greenland. He rushed out to the sunny night around 11 pm.
The resounding noise grew louder as he watched a piece of ice about one-third the size of Manhattan come off the Helheim Glacier. Over the next half-hour, the iceberg was split into pieces and rocked into the water – a fascinating sighting of the sea level rise that the Low have spent years studying.
(Graphic: Greenland project series on climate change – https://tmsnrt.rs/2xvdzOS)
These major glacial breaks, called calving, are rarely observed in person. A Reuters photographer captured the event on video while Holland, an oceanographer from New York University, took the stage "absolutely breathtaking".
"It's amazing how beautiful nature is, how violent and unstoppable she is just doing her own thing," he said. "We have actually seen the process by which the sea level rises glaciers."
Today, Holland and other climate scientists must understand how and how fast the warming of the oceans undermines the glaciers of Greenland and Antarctica. The best predictions for sea-level rise in this century are becoming increasingly difficult, but less accurate, partly because of the lack of understanding of these glaciers and the way their behavior fits into global climate modeling.
(For more stories, graphics and videos from the interactive Greenland Project series, see: https://tmsnrt.rs/2xvdzOS)
A major obstacle to producing better forecasts is the extreme difficulty of the research, which requires dangerous field work on some of the most difficult terrain in the world.
Researchers must deal with winds strong enough to scan screwed equipment; temperatures that may freeze the skin on contact; and remote locations that make securing a daunting challenge.
Security teams help scientists avoid falling into hidden crevices and, in the Arctic, teams arm guns and sleep in fiberglass shelters to avoid becoming a meal for them. polar bears.
The challenges of data collection also require a multitude of creative solutions that scientists refine through trial and error. A NASA team, engaged for three years in a $ 30 million five-year project called Oceans Melting Greenland (OMG), has been using radar to map changes in ice loss over time. dropped the aircraft probes to measure the temperature and salinity of the water at different depths; and ship-mounted sonar instruments for mapping seafloor topography.
The difficulties and dangers associated with access to the waters choked by ice near Greenland's glaciers have led some researchers to call on local wildlife by tagging seals, halibut or narwhal with sensors to collect data.
Researchers at NASA and the Netherlands are focusing on Greenland as it is currently contributing to sea-level rise compared to the colder Antarctic region and because research is very much more difficult in Antarctica.
"It's amazing how difficult it is to do things in Antarctica," said Holland, who has conducted studies in both regions. "The work that can be done here in Greenland on a summer scale takes five to ten years to set up and complete in Antarctica."
$ 20,000
Scientists are concerned that the ongoing calving process in Helheim – named after the world of the Vikings' deaths – provides insights into what could happen on a larger scale in Antarctica. Another Greenland glacier called Jakobshavn has had similar calving events.
In both polar regions, field researchers face serious dangers. Bad weather can prevent researchers for weeks and hidden dangers can hide under the snow. In 2016, Dutch colleague Gordon Hamilton, an American climatologist, was killed in Antarctica when his snowmobile dipped into a crevasse.
The task of keeping the Holland team safe belongs to Brian Rougeux, a former mountaineering guide who has worked in both polar regions. Rougeux, who initially met Holland in 2010 in Antarctica, where Holland served the weather stations, said sudden changes in climate and visibility in Antarctica can sometimes be life threatening.
"You are trying to navigate to a tent in the middle of half a million square kilometers of flat white, with no real terrain features," said Rougeux.
GPS can help, but could lead teams into areas with hidden crevices.
Preparation is the key to efficiency and safety.
"Returning to town for a particular shot takes $ 20,000 of helicopter time, so it becomes a very expensive shot," said Holland.
The challenges of research often persist after the return of field researchers. The data collection tools they leave in place – moorings that monitor the oscillating water temperatures at the radar locked in 10-foot-high protective shells, resembling eggs that take images of melted ice – are vulnerable to the elements. A buoy collecting ocean data for the Dutch team in Greenland was swept away by powerful currents and finally surfaced on a beach in Scotland, and powerful winds washed away other equipment.
HELP LOCAL
Sometimes the conditions are so brutal that researchers must recruit experts: the local wildlife.
In Ilulissat Fiord, in western Greenland, the Holland team uses ringed seals fitted with sensors to record depth, temperature and salinity throughout the entire life of the species. year near Jakobshavn, the fast ice river of the island. They used seals because it was too dangerous to fly a boat across the icy waterway near the glacier, which would have produced the iceberg that sank the Titanic.
"It's hard to find a way by which a robot manufactured by an engineer could do something similar to what a seal can do," Holland said.
Holland had teamed with a local seal biologist, Aqqalu Rosing-Asvid, a former hunter and fisherman. In 2010, they camped on the west coast of Greenland for a week, but did not catch seals. This is only when they next attempt, two years later, that they finally affixed their first seal.
They also use halibut because their deeper swimming helps to monitor the water column closest to the seafloor. The team tagged only fish caught during the hottest days of the fishing season to prevent their eyes from freezing immediately in the cold.
The team relies on fishermen to retrieve the data: Rosing-Asvid's phone number is on the fish tags. "The fishermen call me on the phone and we organize the sending of the label here," he explained.
Last year, three of the 20 halibut sensors were able to return.
Another animal involved in research in the Arctic is the narwhal, an elusive whale with a defense sticking out of the male's head. Marine biologist Kristin Laidre of the University of Washington's Center for Polar Science has already cleaned narwhals to pin a satellite tag to their dorsal ridge "like an earring."
Eidre shared narwhal depth, temperature and salinity records with the NASA team, which is important because the warmer, saltier waters of the Atlantic tend to be underwater cooler and cooler Greenland. Glaciers connected to deep waters melt faster.
"Even today, there are places where we still do not know how deep the water is," said Josh Willis, chief scientist of NASA's OMG project. The marking "gives us the idea that the water in some places is at least as deep as a narwhal dive nearby."
(Report by Lucas Jackson in Greenland and Elizabeth Culliford in New York, edited by Richard Valdmanis and Brian Thevenot)
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