Massive Antarctic Larsen C Ice Shelf Breaks Off: A One Trillion Tonne Iceberg is Floating Away
Geschreven op 25-6-2017 - Erik van Erne. Geplaatst in Klimaat
Update 29 januari 2022: Klimaatnieuws: Kleinere Gletsjers Pope, Smith En Kohler Op Antarctica Smelten Snel
12 July 2017: One of the biggest icebergs on record has broken away from Antarctica. The one trillion tonne iceberg, measuring 5,800 square km, calved away from the Larsen C Ice Shelf in Antarctica sometime between July 10 and 12, said scientists at the University of Swansea and the British Antarctic Survey.
The iceberg, which is likely to be named A68, weighs more than a trillion tonnes. Its volume is twice that of Lake Erie, one of the Great Lakes.
The iceberg weighs more than a trillion tonnes (1,000,000,000,000 metric tonnes), but it was already floating before it calved away so has no immediate impact on sea level. The calving of this iceberg leaves the Larsen C Ice Shelf reduced in area by more than 12%, and the landscape of the Antarctic Peninsula changed forever.
The iceberg is one of the largest recorded and its future progress is difficult to predict. It may remain in one piece but is more likely to break into fragments. Some of the ice may remain in the area for decades, while parts of the iceberg may drift north into warmer waters.
The Larsen A and B ice shelves, which were situated further north on the Antarctic Peninsula, collapsed in 1995 and 2002, respectively.
See also: Antartica: Wilkins IceShelf – Mertz Glacier – RonneFilchner IceShelf – PIG IceShelf - 100 Places To Remember: Ross Ice Shelf, Antarctica - Beneath the Frozen World: Cousteau in Antarctica - Climate Change: Antarctica Ice Melting Fast Global Warming Potential Sea Level Rise - 100 Places To Remember: The Antarctic Peninsula
25 June 2017: British Antarctic Survey (BAS) captured this video footage of a huge crack in the Larsen C Ice Shelf, on the Antarctic Peninsula. Currently a huge iceberg, roughly the size of Norfolk, looks set to break off Larsen C Ice Shelf, which is more than twice the size of Wales.
Satellite observations from February 2017 show a growing crack in the ice shelf which suggests that an iceberg with an area of more than 5,000 km2is likely to calve soon.
Researchers from the UK-based MIDAS project, led by Swansea University, have reported several rapid elongations of the crack in recent years. BAS scientists are involved in a long-running research programme to monitor ice shelves to understand the causes and implications of the rapid changes observed in the region. They shot this footage as they flew over the ice shelf on their way to collect science equipment.
During the current Antarctic field season, a glaciology research team has been on Larsen C using seismic techniques to survey the seafloor beneath the ice shelf. Because a break up looks likely the team did not set up camp on the ice as usual. Instead they made one-off trips by twin otter aircraft supported from the UK’s Rothera Research Station.
Ice shelves in normal situations produce an iceberg every few decades. There is not enough information to know whether the expected calving event on Larsen C is an effect of climate change or not, although there is good scientific evidence that climate change has caused thinning of the ice shelf. Once the iceberg has calved, the big question is whether Larsen C will start to retreat.
See also: Klimaatnieuws Antartica: Wilkins IceShelf – Mertz Glacier – RonneFilchner IceShelf – PIG IceShelf - 100 Places To Remember: Ross Ice Shelf, Antarctica - Beneath the Frozen World: Cousteau in Antarctica - Climate Change: Antarctica Ice Melting Fast Global Warming Potential Sea Level Rise - 100 Places To Remember: The Antarctic Peninsula
Erik van Erne zegt:
20 augustus 2017 om 10:29 | Permalink
West Antarctic Ice Sheet May Hide World’s Largest Volcanic Range
The ice sheets of Antarctica may be hiding the world’s largest volcanic range, according to a new study from the University of Edinburgh. The new work discovered around 100 “new” volcanos in the Antarctic region, some of which are as tall as 3,850 meters.
“They analysed the shape of the land beneath the ice using measurements from ice-penetrating radar, and compared the findings with satellite and database records, as well as geological information from aerial surveys.
“Scientists found 91 previously unknown volcanoes, ranging in height from 100 to 3850 metres. The peaks are concentrated in a region known as the West Antarctic Rift System, spanning 3,500 kilometres from Antarctica’s Ross Ice Shelf to the Antarctic Peninsula.
“… Their results do not indicate whether the volcanoes are active, but should inform ongoing research into seismic monitoring in the area. Volcanic activity may increase if Antarctica’s ice thins, which is likely in a warming climate, scientists say. Previous studies and the concentration of volcanoes found in the region together suggest that activity may have occurred in previous warmer periods.”