Εμφάνιση αναρτήσεων με ετικέτα Antarctic. Εμφάνιση όλων των αναρτήσεων
Εμφάνιση αναρτήσεων με ετικέτα Antarctic. Εμφάνιση όλων των αναρτήσεων

Δευτέρα, 15 Σεπτεμβρίου 2014

Glaciers in northern Antarctic Peninsula melting faster than ever despite increased snowfall

An international team of researchers, led by Dr Bethan Davies, from Royal Holloway, University of London, has discovered that small glaciers that end on land around the Antarctic Peninsula are highly vulnerable to slight changes in air temperature and may be at risk of disappearing within 200 years.

Temperatures are currently rising rapidly in the Antarctic Peninsula. Because warmer air holds more moisture, the amount of snowfall has also increased. Some researchers have suggested that this may offset the melting of the glaciers, however this study found that just a small rise in air temperature increased melting so much that even large amounts of extra snowfall could not prevent glacier recession.

"These small glaciers around the edge of the Antarctic Peninsula are likely to contribute most to rising sea levels over the coming decades, because they can respond quickly to climate change," said Dr Davies, from the Department of Geography at Royal Holloway. "This study is the first to show how glaciers in this vulnerable region are likely to respond to climate change in future. Our findings demonstrate that the melting will increase greatly even with a slight rise in temperature, offsetting any benefits from increased snowfall."

The researchers carried out extensive fieldwork on James Ross Island, northern Antarctic Peninsula, to map and analyse the changes to a glacier, which is currently 4km long, over the past 10,000 years. They used a combination of glacier and climate modelling, glacial geology and ice-core data.

Dr Davies added: "Geological evidence from previous studies suggests that the glacier grew by 10km within the last 5,000 years, before shrinking back to its current position. It was argued that this occurred during a warmer but wetter period, suggesting that increased precipitation in the future would offset the melting of the glaciers. However, our study shows that this growth occurred during the colder 'Little Ice Age', reaching its largest size just 300 years ago."

Researcher Dr Nicholas Golledge, from Victoria University of Wellington, in New Zealand, said: "This glacier, though small, is typical of many of the small glaciers that end on land around the Antarctic Peninsula. This research is important, because it helps reduce some of the uncertainties about how these glaciers will react to changing temperature and precipitation over the next two centuries."

Professor Neil Glasser, from Aberystwyth University, added: "We found that this glacier remained roughly the same size for thousands of years until it started to grow again 1,500 years ago. However, it is now melting faster than anything seen before, and over the next 200 years will become far smaller than at any point over the last 10,000 years. This unprecedented glacier recession, in response to climate change, will result in significant contributions to sea level rise from this and similar Antarctic Peninsula mountain glaciers and ice caps."



Τρίτη, 5 Αυγούστου 2014

Soviet-era satellite burns up in atmosphere after 34 years of service

The Kosmos-1151, a Soviet-era satellite appears to have burned up upon reentry into the Earth’s atmosphere, Russian Aerospace Defense Forces spokesman Colonel Alexei Zolotukhin said Tuesday.

“The data analysis … has proven that the Kosmos-1151 spacecraft left its orbit,” Zolotukhin said.

According to experts, parts of the satellite burned up in the dense layers of atmosphere over the Antarctic.

The Kosmos-1151 was launched into orbit on January 23, 1980. The expected lifetime of a satellite in orbit is about half a year.


Τρίτη, 13 Μαΐου 2014

Ice Loss from Antarctic Glacier Unstoppable

A large portion of the West Antarctic Ice Sheet is melting rapidly, and appears to be in an irreversible state of decline. That assessment, from a new study by researchers at NASA and the University of California, Irvine, finds that there is nothing to stop the glaciers in the area from melting into the sea.

Glaciologist and lead author Eric Rignot told a news conference Monday that the melting will be a major contributor to sea level rises in the decades and centuries to come.

"We and many other colleagues have looked extensively at this part of the world over the last two decades, with satellites, airplanes, ships and ground survey. We have examined enough direct and independent observations of this part of the world to conclude that the retreat of ice in that sector is unstoppable," said Rignot.

The glaciers in the Amundsen Sea sector of West Antarctica contain enough ice to raise the global sea level by more than a meter, and are melting faster than most scientists had expected. They already release almost as much ice into the oceans annually as the entire Greenland Ice Sheet.

The report, which appears in the journal Geophysical Research Letters, concludes: "The fact that the retreat is happening simultaneously over a large sector suggests it was triggered by a common cause, such as an increase in the amount of ocean heat beneath the floating sections of the glaciers. At this point, the end of this sector appears to be inevitable." 

  • The researchers say while cutting CO2 emissions could slow the glacier loss, they stress it could not reverse it.

For additional images and video related to this new finding, visit: http://go.nasa.gov/1m6YZSf

For additional information on the West Antarctic Ice Sheet and its potential contribution to sea level rise, visit: http://go.nasa.gov/1oIfSlO


Σάββατο, 26 Απριλίου 2014

NO EXCUSES: WE NEED TO PROTECT THE ANTARCTIC. - Only less than one percent of the world’s oceans are currently set aside as “protected”

Maria Damanaki, Commissioner for Maritime Affairs and Fisheries:

"Did you know that only less than one percent of the world’s oceans are currently set aside as “protected”? Only a handful of those areas are spared human interference altogether. Today’s International Penguin Day reminds us of the need to protect Antarctic habitats before it’s too late. If we are to save the last remaining pockets of pristine ocean and the thousands of unique species living there, we need to act fast.

Some progress has been made: through international efforts, the first marine protected area in the Southern Ocean was adopted in 2009. Near the South Orkney Islands fishing is now banned except for scientific purposes. We are still on a learning curve and it may be a few years before it runs completely smoothly. But in the meantime the site’s krill and squids will have fed generations of Antarctic penguins. We are now moving to the next step – there are currently proposals to protect the waters of East Antarctica and the Ross Sea before the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) that deserve international support. A decision could be taken in October already.

The fact that these areas are part of the common good does not grant us a free pass to do nothing. On the contrary: the EU is also fighting for an international agreement to cover precisely those areas which fall through the net of direct responsibility of any one country. And we are aiming for this by next year.

Turning back the clock on ecosystems is an urgent matter, and one that I’m not comfortable postponing. No excuse there."

International Penguin Day

Σάββατο, 8 Φεβρουαρίου 2014

Pôle sud: la Chine ouvre sa 4e station scientifique

La Chine a ouvert sa quatrième station scientifique baptisée Taishan en Antarctique, rapporte samedi l'agence Chine nouvelle se référant au bureau national des affaires océaniques.

Située à 2.600 m d'altitude entre les stations chinoises Zhongshan et Kunlun, la nouvelle base scientifique fonctionnera pendant la période estivale pendant les 15 prochaines années. Elle pourra accueillir jusqu'à 20 personnes. La station est dotée d'une piste d'atterrissage.

La Chine a envoyé pour la première fois des chercheurs en Antarctique en 1984. Sa première base scientifique antarctique Chángchéng zhàn ("Grande muraille") fonctionne depuis 1985.

Les médias chinois ont antérieurement annoncé que Pékin comptait porter le nombre de ses stations scientifiques en Antarctique à cinq d'ici 2015.

Sur le même sujet:

Δευτέρα, 6 Ιανουαρίου 2014

Xuelong to try and free itself from the ice

A Chinese icebreaker stuck in the Antarctic has cleared a path through the ice one kilometer in length.

The deputy director of the Xue Long, or Snow Dragon, says the vessel will use the channel to pick up as much speed as possible in order to free itself from the ice. 

The team, which has enough water to last them a month, is now waiting for favorable weather conditions.

The Xue Long became trapped in ice after helping in the rescue of passengers of a Russian research ship. On Sunday morning, the US sent its own icebreaker, the Polar Star, to assist Xue Long and the Russian vessel.


Κυριακή, 17 Νοεμβρίου 2013

Could volcanoes be causing Antarctic ice loss?

AFP - Accelerating ice loss from the Antarctic ice sheet could be due in part to active volcanoes under the frozen continent's eastern part, a study said on Sunday.
From 2002 to 2011, the average annual rate of Antarctic icesheet loss increased from about 30 billion tonnes to about 147 billion tonnes, the UN's panel of climate scientists reported in September.
The icesheet is a mass of glacial land ice -- one such sheet covers most of Greenland and the other Antarctica, and together they contain most of the freshwater on Earth.
The sheets are constantly moving, slowly flowing downhill and seawards under their own weight. Portions that extend out over the water are called ice shelf.

Previous research has blamed warmer seas swirling in a circular fashion around Antarctica for the quicker pace of icesheet loss from the southernmost continent.
These waters erode ice shelves, went the theory. And as more of the shelves disappeared, the quicker the sheet would flow and lose ice to the sea.
But in a new paper in the journal Nature Geoscience geologists led by Amanda Lough at Washington University in St. Louis, Missouri, suggested that, in West Antarctica, the faster flow may be also be due to volcanoes.
These heat the underside of the ice, causing melting that lubricates the flow, they suggested.
Evidence for this comes from recently deployed sensors that recorded two "swarms" of seismic activity under Mary Byrd Land, a highland region of West Antarctica, in 2010 and 2011.
Using ice-penetrating radar, the team found an intriguing elliptically-shaped deposit, measuring about 1,000 square kilometres (386 square miles) in the area, at a depth of 1,400 metres (4,550 feet).
  • The deposit is believed to be volcanic ash, spewed out by an enormous eruption some 8,000 years ago -- an estimate reached on the assumption it has since been covered by ice accumulating at the rate of 12.5 centimetres (five inches) a year.
"Together, these observations provide strong evidence for ongoing magmatic activity and demonstrate that volcanism continues to migrate southwards."
Several volcanoes were known to exist in West Antarctica, but none were thought to be active.
"Eruptions at this site are unlikely to penetrate the 1.2 to two-km (0.75-1.2-mile) -thick overlying ice, but would generate large volumes of melt water that could significantly affect ice stream flow," said the study.

Πέμπτη, 24 Οκτωβρίου 2013

Θα παραμείνει η Ανταρκτική τόπος ερευνών; -Οι 49 χώρες που έχουν προσυπογράψει τη Συνθήκη της Ανταρκτικής συναντώνται κάθε χρόνο εκ περιτροπής.

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Όχι στην εξόρυξη πετρελαίου ή άλλου ορυκτού πλούτου. Η Συνθήκη της Ανταρκτικής προβλέπει ότι ο Νότιος Πόλος είναι και θα παραμείνει τόπος έρευνας, παρά τις εδαφικές αξιώσουν που έχουν επτά χώρες.

Ποιος ασχολείται όταν στην Ανταρκτική βυθιστεί ένα πλοίο ή πέσει κάποιο αεροπλάνο; Ποιος μπορεί να εγγυηθεί ότι η αποκαλούμενη λεύκη ήπειρος δεν θα γίνει πεδίο αναζήτησης και εξόρυξης ορυκτού πλούτου; «Η τεράστια αυτή ήπειρος των 14 εκ. τετραγωνικών χλμ βρίσκεται εκτός εθνικής δικαιοδοσίας», εξηγεί ο Μάνφρεντ Ράινκε στο μικρόφωνο της DW. Ο Γερμανός ειδικός είναι από το 2009 αποκλειστικός γραμματέας της Συνθήκης της Ανταρκτικής, η οποία ρυθμίζει ότι αφορά το Νότιο Πόλο: από τα εδάφη και τις θαλάσσιες περιοχές, μέχρι τα ατυχήματα ή τον ορυκτό πλούτο.

Η εν λόγω Συνθήκη υπογράφηκε το 1959 εν μέσω Ψυχρού Πολέμου. Κάθε χώρα μπορεί να προσχωρήσει ωστόσο μόνο εκείνες που έχουν πραγματοποιήσει επιστημονικές αποστολές στην ήπειρο διαθέτουν δικαίωμα ψήφου. Οι 49 χώρες που έχουν προσυπογράψει τη Συνθήκη της Ανταρκτικής συναντώνται κάθε χρόνο εκ περιτροπής.
Ο Μάνφρεντ Ράινκε πιστεύει ότι η μεγαλύτερη επιτυχία στην Ανταρκτική μέχρι σήμερα είναι η διεθνής συνθήκη που προβλέπει ειρηνικές έρευνες στην ήπειρο, παρά τις εδαφικές αξιώσεις που εγείρουν επτά χώρες. Και σημειώνει ότι το 1991 προστέθηκε στη Συνθήκη της Ανταρκτικής ένα επιπλέον άρθρο για την προστασία του περιβάλλοντος που απαγορεύει ρητά την εκμετάλλευση του ορυκτού πλούτου συμπεριλαμβανομένων του πετρελαίου και του φυσικού αερίου.

Εντείνεται η πίεση για την εμπορική αξιοποίηση.

Σε αντίθεση στο Βόρειο Πόλο στην Αρκτική το λιώσιμο των πάγων διευκολύνει πολλές οικονομικές δραστηριότητες με ολέθριες συνέπειες. Δημιουργήθηκαν νέες δίοδοι για τα πλοία, ενώ την ίδια στιγμή ξεκίνησε η αναζήτηση πετρελαίου, φυσικού αερίου και ορυκτών. Θα μπορούσε να γίνει κάτι παρόμοιο να γίνει και στην Ανταρκτική; Ο Αλέν Χούμπερτ, ειδικός σε ζητήματα πολιτικού κύκλου, πιστεύει ότι η πίεση για την εμπορική αξιοποίηση του Νοτίου Πόλου θα αυξηθεί το επόμενο διάστημα. Και φέρνει ως παράδειγμα τη μείωση σε ορισμένες θαλάσσιες περιοχές των αποθεμάτων κριλ, των μικροσκοπικών οργανισμών που παίζουν καθοριστικό ρόλο στο οικοσύστημα της λευκής ηπείρου.
Μια ευκαιρία να επιλυθεί το πρόβλημα της υπεραλίεσης σε ορισμένες περιοχές της Ανταρκτικής μέσα από τον ορισμό ειδικών ζωνών προστασίας είναι το ενδεχόμενο υπογραφής ειδικής συμφωνίας μεταξύ εκπροσώπων 24 χωρών και της ΕΕ που ξεκίνησε χθες στο Χόμπαρτ της Αυστραλίας. Στο τραπέζι υπάρχουν δύο προτάσεις να απαγορευθεί η αλιεία σε μια θαλάσσια περιοχή με διαστάσεις πέντε φορές το εμβαδόν της Γαλλίας. Το αποτέλεσμα της ψηφοφορίας παραμένει ωστόσο ανοιχτό.
Irene Quaile / Στέφανος Γεωργακόπουλος
Υπεύθυνη σύνταξης: Μαρία Ρηγούτσου



Παρασκευή, 1 Μαρτίου 2013

‘Intrigue’ Persists in Hunt for Antarctic Subglacial Life

MOSCOW, March 1 (Alexey Eremenko, RIA Novosti) – Russian researchers have successfully obtained ice samples from the ancient Lake Vostok in the Antarctic, but said on Friday it would take months to clarify whether life exists in the fossil water below the 3.5-kilometer (2.2 mile) high glacier.
“Let’s maintain the intrigue a little longer,” Vladimir Lipenkov, a climatologist at Russia’s Arctic and Antarctic Research Institute, quipped at a RIA Novosti press conference.

The ice samples are currently on the research vessel Akademik Fyodorov, which will return to St. Petersburg from the Southern hemisphere in May, Lipenkov said. Analysis of the samples will then start, with results published in late 2013 or early next year, he said.
Lake Vostok, the largest subglacial lake in the Antarctic, may contain unique microscopic lifeforms that evolved after it was isolated from the outside world by the ice sheet 18 million years ago, Lipenkov said at a conference in St. Petersburg, broadcast to Moscow via videolink.
Russian researchers have been drilling to reach the lake since 1995, completing the borehole last year. However, the drilling season is short due to the harsh weather conditions in the area – Lake Vostok is situated at the southern Pole of Cold – and the research team was only able to collect samples of surface water from the lake that froze in the borehole in January 2013.
No lifeforms are currently known which would be capable of surviving in environment such as in the Lake Vostok, where the concentration of oxygen is 50 times higher than in ordinary water, Lipenkov said.
Preliminary analysis of early samples of surface water from the lake, published late last year, found no traces of any unique bacteria. But microorganisms may be living closer to the bottom, next to thermal springs which may be there, Lipenkov said.
The next step in the research will be obtaining water samples from below the surface of the lake, which has an average depth of more than 300 meters (980 feet), and then drill for bottom sediments, said drilling expert Nikolai Vasilyev.
That task will be harder than obtaining samples of lunar and Martian soil, said Vasilyev, a researcher with the National Mineral Resources University in St. Petersburg, which oversees the drilling operations at Lake Vostok.
The expedition at Russia’s Vostok Station above the lake was cleared by the international Committee for Environmental Protection to continue its research through 2018, said Valery Lukin, the head of the Russian Antarctic Expedition.
Russia allotted about 1.1 billion rubles ($35 million) to support Antarctic research in 2012, with 465 million rubles ($15 million) of that sum spent on Vostok Station, Lukin said at the conference.
The station, established in 1957, is one of five Russian year-round bases in the Antarctic. It is tentatively scheduled for a major revamp of its facilities starting 2014, Lukin said.
The Antarctic remains one of the least explored places on the planet, and as such, continues to thrill researchers and explorers. Caving in to temptation, even Russian President Vladimir Putin – known for his flamboyant exploits such as flying with migratory birds in a hang-glider and diving to the bottom of Lake Baikal in a submersible – announced in January plans to tour Russia’s stations on the southern continent sometime in 2013.
Some theories about the mysteries of the Antarctic are quite far-fetched: An oft-cited story claims a secret Nazi base was established there in 1943 to store Hitler’s secret files and DNA for cloning purposes. The story was never confirmed by historians, but continues to thrill conspiracy theorists.
The real mysteries of the Antarctic have to do with life under extreme conditions, which are similar to those found outside the Earth, Lukin said. Jupiter’s moon Europa is believed to house an ocean of liquid water under an outer core of ice, similar to Lake Vostok – and if the latter proves to contain life, this may imply similar discoveries on Europa.
“I’d compare it to space research,” Lukin said of Antarctic exploration. “Understanding of the subglacial environment expands human knowledge, the same as studying other objects of the Solar System.”


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