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1-Mile Long Rectangular Iceberg Calves from Larsen C

Nasa has released striking photos of a rectangular iceberg floating in the Weddell Sea off Antarctica. Such objects are not unknown, however, and even have a name – tabular icebergs.

The US space agency said the object’s sharp angles and flat surface suggested it had recently broken away from an ice shelf.

The edges are still pointed, and have not yet been worn down by the ocean waves.

Kelly Brunt, a glaciologist with Nasa and the University of Maryland, said the process of formation was a bit like a fingernail growing too long and cracking off at the end.

This particular ‘berg came from the Larsen C ice shelf on the Antarctic Peninsula — an area with 16 active or semi-active volcanoes directly beneath it.

In July 2017, Larsen C released the massive A68 iceberg, a chunk of ice about the size of the state of Delaware.

A68 iceberg calving from Larsen C. July 2017

CALVING

As ice sheets grow a process called ‘calving’ occurs.

Calving, also known as glacier calving or iceberg calving, is the breaking of ice chunks from the edge of a glacier. It is a form of ice ablation or ice disruption and is normally caused by the glacier expanding — not melting!

When calving occurs freshwater gets injected into the ocean.

Large influxes of freshwater can disrupt deep-water systems resulting in impacts on climate.

A research team led by Woods Hole Oceanographic Institution (WHOI) recently found the fingerprint of a massive flood of freshwater in the western Arctic, likely to be the cause of an ancient cold snap that began around 13,000 years ago — for that article in full, click here.

It’s clear to the researchers that this huge influx of freshwater from caving ice sheets disrupted the Atlantic Meridional Overturning Circulation (AMOC), with the upshot being rapid global cooling.

The AMOC hasn’t been running at peak strength since the mid-1800s and is currently at its weakest point in the past 1,600 years.

As the Grand Solar Minimum continues its intensification, it is thought ever-expanding ice sheets and the resulting calving will further weaken deep-water systems, disrupting weather patterns across the globe.

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[Featured Image: NASA/Jeremy Harbeck]

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