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Rapid Decay Indicated By Giant Cavity In Antarctic Glaciers

The melting rate on this side of the glacier is extremely high.

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A glacier is shown in a photo taken in Half Moon Bay, Antarctica, Feb. 18, 2018.
A glacier is shown in a photo taken in Half Moon Bay, Antarctica, Feb. 18, 2018. VOA

Scientists from NASA have discovered a gigantic cavity, almost 300 metres tall, growing at the bottom of the Thwaites Glacier in West Antarctica, indicating acceleration in rising global sea levels due to climate change.

The size of the cavity, at Thwaites’ bottom where ocean water could flow in and melt the glacier from below, is big enough to have contained 14 billion tonnes of ice.

Importantly, most of that ice melted over the last three years, the findings showed.

“(The size of) a cavity under a glacier plays an important role in melting,” said lead author Pietro Milillo of NASA’s Jet Propulsion Laboratory (JPL) in California.

Antarctica, Ice
The Collins glacier on King George Island has retreated in the last 10 years and shows signs of fragility, in the Antarctic, Feb. 2, 2018. VOA

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

The cavity, reported in the Science Advances journal, was revealed by ice-penetrating radar in NASA’s Operation IceBridge — an airborne campaign beginning in 2010 that studies connections between the polar regions and the global climate.

Thwaites Glacier is currently responsible for approximately 4 per cent of global sea level rise.

It holds enough ice to raise the world’s oceans a little over 2 feet and backstops neighbouring glaciers that would raise sea levels to an additional 8 feet if all the ice were lost.

Antarctica
Antarctica melting away at alarming rate: Study. Flickr

Thwaites is one of the hardest places to reach on Earth, but it is about to become better known than ever before.

The huge cavity was under the main trunk of the glacier on its western side – the side farther from the West Antarctic Peninsula.

In this region, as the tide rises and falls, the grounding line retreats and advances across a zone of about 3 to 5 km. The glacier has been coming unstuck from a ridge in the bedrock at a steady rate of about 0.6 to 0.8 km a year since 1992.

Also Read: Global Greenhouse Gas Level Continues To Rise, Need For a New Political and Investment Paradigm

Despite this stable rate of grounding-line retreat, the melting rate on this side of the glacier is extremely high.

These results highlighted that ice-ocean interactions were more complex than previously understood. (VOA)

Next Story

2 Big Asteroids Flying by Earth Pose no Risk: NASA

At the start of 2019, the number of discovered NEOs totaled more than 19,000, and it has since surpassed 20,000. An average of 30 new discoveries are added each week, NASA said

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NASA Headquarter in USA, VOA

NASA has ruled that the pair of asteroids flying by Earth this weekend could pose a threat to our planet.

“These asteroids have been well observed – once since 2000 and the other since 2010 – and their orbits are very well known,” said NASA’s Planetary Defence Officer Lindley Johnson.

“Both of these asteroids are passing at about 14 lunar distances from the Earth, or about 3.5 million miles away, but small asteroids pass by Earth this close all the time,” Johnson said.

Near-Earth asteroid 2010 C01, estimated to be 120 to 260 metres in size, safely passed Earth at 3.42 a.m. on Saturday. The second object, 2000 QW7 is estimated to be 290 to 650 metres in size will pass later at 11.54 p.m. on Saturday.

NASA
Earth’s view from moon’s surface. Pixabay

Near-Earth objects (NEOs) are asteroids and comets that orbit the Sun, but their orbits bring them into Earth’s neighborhood – within 30 million miles of Earth’s orbit.

These objects are relatively unchanged remnant debris from the solar system’s formation some 4.6 billion years ago.

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Most of the rocky asteroids originally formed in the warmer inner solar system between the orbits of Mars and Jupiter, while comets, composed mostly of water ice with embedded dust particles, formed in the cold outer solar system.

At the start of 2019, the number of discovered NEOs totaled more than 19,000, and it has since surpassed 20,000. An average of 30 new discoveries are added each week, NASA said. (IANS)