NASA Discovers Massive Cavity Below a Glacier in Antarctica

POLAR PANIC:
‘World’s most dangerous glacier’ could COLLAPSE within decades and ‘sink cities’ as Nasa discovers 1,000-foot ‘doomsday’ cavity lurking below

AN ENORMOUS lump of ice dubbed the “world’s most dangerous glacier” is teetering on the verge of collapse, threatening to raise global sea levels by an unprecedented eight feet.

Nasa has discovered a gigantic cavity under the Thwaites Glacier in West Antarctica that they say could destabilise the doomsday ice block and topple it into the sea.

Its top boffins warned that the growing hole is already as tall as London’s Shard skyscraper, and covers an area the size of 10,000 football pitches.

As it grows, Thwaites will disintegrate faster and faster, potentially triggering a global catastrophe.

“[The size of] a cavity under a glacier plays an important role in melting,” said Nasa scientist Dr Pietro Milillo.

“As more heat and water get under the glacier, it melts faster.”

The gigantic Thwaites glacier covers 113,000 square miles – about half the area of the United Kingdom.

If it melts, global sea levels will rise by over 2 feet, causing coastal flooding that will turf hundreds of thousands of people across the globe from their homes.

But it’s Thwaites protective effect on neighbouring glaciers that Nasa is most worried about.

They say the ice chunk acts as a “backstop” that stops others around it from melting.

Without it, surrounding glaciers could all disintegrate, raising sea levels by 8 feet if all ice were lost.

This would put large swathes of coastal cities underwater, turning streets into canals and completely submerging some towns and cities.

Previous research has predicted that a 6ft sea level rise would leave large parts of Kent underwater, while Portsmouth, Cambridge and Peterborough wouldn’t fair much better.

Nasa found a huge growing cavity under Thwaites while examining ice-penetrating satellite imagery of Thwaites.

The research is part of Nasa’s Operation IceBridge, which uses space snaps to track the effects of climate change.

They say the hole is big enough that the glacier has already lost 14billion tons of ice in the past three years.

Researchers expected to find some gaps between ice and bedrock at Thwaites’ bottom where ocean water could flow in and melt the glacier from below.

However, the size and “explosive growth rate” of the newfound hole surprised them.

“We have suspected for years that Thwaites was not tightly attached to the bedrock beneath it,” said team member Professor Eric Rignot, a scientist at the University of California.

“Thanks to a new generation of satellites, we can finally see the detail,” he said.

The results highlight the need for better observations of the undersides of glaciers to track how they are hit by climate change.

“Understanding the details of how the ocean melts away this glacier is essential to project its impact on sea level rise in the coming decades,” Professor Rignot said.

The study was published in Science Advances.

source: thesun.co.uk

اكتشف علماء في وكالة الفضاء الأميركية «ناسا» كتلة من الجليد الهائل، أطلق عليها اسم «أكثر الأنهار الجليدية خطورة في العالم»، تتأرجح على حافة الانهيار، ما يهدد برفع مستويات البحار العالمية بمقدار 8 أقدام، حيث أحدثت تجويفاً هائلاً غرب منطقة القطب الجنوبي «أنتاركتيكا»، يمكن أن يزعزع استقرار كتلة جليد «يوم القيامة»، ويطيح بها في البحر.

وحذّر علماء «ناسا» من أن التجويف المتنامي يصل طوله بالفعل إلى طول ناطحة سحاب «Shard» في العاصمة البريطانية لندن، ويغطي مساحة بحجم 10 آلاف ملعب كرة قدم، ومع نموها تتفكك بسرعة كبيرة، ما قد يؤدي إلى كارثة عالمية.

وقال بيترو ميليلو عالم بوكالة «ناسا»، إن حجم التجويف الواقع تحت النهر الجليدي يلعب دوراً مهماً في الانصهار، حيث يزداد معدل الذوبان مع ارتفاع درجات الحرارة، ويغطي نهر «Thwaites» الجليدي الضخم مساحة 113 ألف ميل مربع، أي ما يعادل نصف مساحة المملكة المتحدة، وفي حال ذوبانه فإن مستويات مياه البحار العالمية سترتفع بأكثر من قدمين، ما يتسبب في فيضانات ساحلية ستؤدي إلى نزوح مئات الآلاف من الناس في جميع أنحاء العالم من منازلهم.

وأوضحت «ناسا» أن نهر «Thwaites» يحمل تأثيراً وقائياً يحمي الأنهار الجليدية المجاورة مما يمنعها من الذوبان، وبدون ذلك يمكن أن تتفكك، ما يرفع مستويات البحار بمقدار 8 أقدام حال ذوبان الجليد بالكامل.;