A word from the editor. Dear followers, on December 26th 2017 a mean hacker attack invalidated the entire Montecarlotimes’website. Today we are pleased to update some of the most liked posts. Yours truly, Ilio Masprone – Knight of the Principality of Monaco for cultural merits, with the Team.
by Enrica Guidotti MONACO. The break of the Larsen C Ice Shelf A68 that broke off Antarctica in July 2017 is not a warning of imminent sea level rise… It may “simply be a rare but natural occurrence”, BUT CLIMATE CHANGE IS…CLIMATE CHANGE! Scientists continue to study and debate what caused A68 to break off, including the role of climate change driven by human activity. “To me, it’s an unequivocal signature of the impact of climate change on Larsen C,” Eric Rignot, a glaciologist at NASA JPL, told CNN in July 2017. “This is not a natural cycle. This is the response of the system to a warmer climate from the top and from the bottom. Nothing else can cause this.”
One year ago, a US satellite observed the berg while passing over a region known as the Antarctica’s Larsen C Ice Shelf. The event was confirmed by other spacecraft such as Europe’s Sentinel-1 satellite-radar system. Scientists were expecting it. They’d been following the development of a large crack in Larsen’s ice for more than a decade. “The rift was barely visible in the data in recent weeks, but the signature was clear as it opened considerably along its whole length before breaking,” explained Prof Adrian Luckman, whose Project Midas at Swansea University is following the berg’s evolution closely. Here the work in progress in the year 2017-2018: between May 25 and May 31 the rift in the Larsen C Ice Shelf grew an additional 17 km (11 miles) in the largest jump since January 2017. This has moved the rift tip to within 13 km (8 miles) of breaking all the way through to the ice front, producing one of the largest ever recorded icebergs. The rift tip appeared also to have turned significantly towards the ice front, indicating that the time of calving was probably very close. The rift fully breached the zone of soft ‘suture’ ice originating at the Cole Peninsula and there appeared to be very little to prevent the iceberg from breaking away completely.
On July 12 2017, data from the Sentinel-1 satellite confirmed the calving from the Larsen C Ice Shelf of Iceberg A68, a slab of ice weighing more than 1 trillion tonnes and 5,800 km in area – around three time the size of the Principality of Monaco …New Sentinel-1 interferometry data from July 18 showed how the remaining ice shelf was responding to the calving event. One year after calving, iceberg A68a has floated about 40 miles away from its birthplace. A68a is wandering north, where it should eventually break up and melt. Although the process may take a few years, some large icebergs survive for decades. British astronaut Tim Peake photographed one berg from orbit that would just about fit inside Central London’s ring road. But at 26km by 13km or 340km in area, it was a toddler compared with the berg that broke away from the eastern side of the Antarctic Peninsula. What’s nice about Tim’s berg is that he managed to capture it on a normal SLR optical camera. That’s unusual because Antarctica is very often covered in cloud, and it doesn’t matter how big a lens you have – the ocean surface will be obscured. It’s why radar satellites are so important. The wavelengths they have work at pierce cloud and winter darkness. Indeed, the only reason we know this new Larsen berg was about to calve is because Europe’s Sentinel-1 radar satellites take a detailed look at the shelf’s behaviour every six days. “What the current Larsen situation has highlighted is that we’re now able to monitor the situation with a frequency we’ve never had before,” said Dr Hogg. “We can get pictures from the two Sentinel-1 satellites in about half an hour of them being acquired. The satellites we have now are revolutionising our study of the polar regions,” she told BBC News.
Everybody is fascinated by icebergs. The idea that you can have blocks of frozen water the size of cities, and bigger, sparks our sense of wonder. Now, I think that it is important to knowledge something more about the code name of Anctactica icebergs: a) Icebergs are blocks of ice that cover at least 500 sq (one zero less than Larsen C…); b) many are smaller and they are called “growlers” or “bergy bits”; c) the US National Ice Center runs the naming system for berg; d) it divides Antarctica into quadrants – A, B, C and D.; e) Larsen icebergs get an “A” designation when they calve. f) They also get the next number in the sequence of sightings. Therefore, the full name of this Antarctic thick tabular berg more than 200m is: Larsen C ice shelf of iceberg A68. The Larsen C Ice Shelf A68 has lose more than 10% of its area to leave the ice front at its most retreated position ever recorded; this spectacular event will fundamentally change the landscape of the Antarctic Peninsula. The new configuration will be less stable than it was prior to the rift. Larsen C may eventually follow the example of its siblings Larsen B, Larsen A and Larsen B, which collapsed and disintegrated in 1995 and 2002, respectively; Larson B doing so in spectacular style, following a similar rift-induced calving event. It also happened that a mega-berg (A-38) turned up in 2004. The Larsen C Ice Shelf A68 is now a giant ‘white wanderer’, a floating projection from the Peninsula that is a quarter of Switzerland, more or less like the entire Geneva lake region. It will not move very far, very fast in the short term but it will need to be monitored. It is timely work because there is considerable interest currently in the status of the Larsen C Ice Shelf. How? First above all, iceberg “doodles” trace climate history (it is as if a child has been doodling with large coloured crayons).
Second, Antarctica’s troublesome “hairdryer winds” blow no good – at least not for the ice shelves on the eastern side of the Antarctic Peninsula. A new study has found an atmospheric melting phenomenon in the region to be far more prevalent than anyone had realised. This is the foehn winds that drop over the big mountains of the peninsula, raising the temperature of the air on the leeward side well above freezing. The warming effect of the foehn winds is felt at least 130km across the ice shelf. The dominant winds blowing in the Antarctic Peninsula region are westerlies; as their air parcels rise over the mountains, they cool and lose their moisture; the descending air parcels (foehn wind) on the other side are therefore dry; leeward air is also 5-10 degrees warmer than the equivalent windward altitude. “In summer, we expect some melt, around 2mm per day. But in spring we’re having an equal amount of melt as we are in summer during the foehn winds,” Ms Turton told in her presentation of the foehn research at the European Geosciences Union General Assembly in Vienna.
Third, there is the question about where the graveyard of giant iceberg is: well, South Georgia, between Antarctica and the South America East Coast, is the place where colossal icebergs go to die. The huge tabular blocks of ice that frequently break off Antarctica get swept towards the Atlantic and then ground on the shallow continental shelf that surrounds the 170km-long island. As they crumble and melt, they dump billions of tonnes of freshwater into the local marine environment. A group of scientists planted scientific moorings off South Georgia in several hundred metres of water. The moorings held sensors to monitor the physical properties of the water, including temperature, salinity and water velocity. The presence of plankton was also measured. The moorings were in prime position to capture what happened when the mega-berg A-38 turned up in 2004.
At South Georgia, the giants may on occasions have a more negative consequence, especially in the case of an A-68! A team of scientists leaded by Professor Murphy lis ooking at the physics of this problem to see if they can then examine how it may have affected the biology that mega-bergs could have important biological impacts. Dust and rock fragments picked up in Antarctica act as nutrients when they melt out into the ocean, fuelling life such as algae and diatoms right at the bottom of food webs. Some of the data collected by researchers across the territory leads the team to think the berg’s great bulk could act as a barrier to the inflow of krill. These shrimp-like creatures follow the same currents as the bergs and are a vital source of food to many of the island’s animals, including its penguins, seals and birds. In years when there are few krill at South Georgia, the predators that eat them will suffer poor breeding success. “In really bad years, the beaches of South Georgia can be littered with dead pups and chicks…” Professor Murphy says. As for the Principality of Monaco we are proud to report on of the many projects supported by the Prince Albert II Foundation titled “Identifying potential Marine Protected Areas in South Georgia that reads: “The Scotia Sea and the seas surrounding South Georgia form a unique ecosystem in the Southern Ocean. South Georgia Island, a British Overseas territory with a land area of 3,755 km2, has a varied subantarctic-type fauna, although it lies to the south of the polar front. This region provides essential shelter for many pelagic species.”
Protecting some of them is a crucial issue: it has become essential to identify and protect key marine habitats in the neighbouring waters. The aim of this project is to use the birds and other marine predators as indicator species of marine biological hotspots in the South Georgia and Scotia region of the Southern Ocean. This study will enable us to identify and classify the most relevant areas in terms of biodiversity, but also to define the most appropriate management approach for the future marine protected areas.