Ancient Penguin Bones :
The ice age isn’t uncommon for our planet as it has seen many times even before the dawn of civilization.
And what’s more disturbing is that the world’s largest glacier located in Antarctica – Thwaites Glaciers and Pine Island are losing their ice cover at a much faster rate than they have at any time in the last ice ages.
Image credit: NASA/Brooke Medley
This shocking truth was found by researchers studying penguin bones and Limpet shells.
What’s more alarming is that the 2 of Antarctica’s fastest-shrinking glaciers are on course for unstable, runaway retreats.
Using penguin bones and shells to reconstruct the glaciers’ history, the researchers are trying to figure out if these glaciers have ever been smaller than they are today.
The research report was published in Nature on June 9th. “If the ice has been smaller in the past and did readvance that shows that were not necessarily in runaway retreat right now,” said glacial geologist Brenda Hall of the University of Maine in Orono.
However, “the new result doesn’t give us any comfort. We can’t refute the hypothesis of a runaway retreat,” she added citing at the fast-retreating ice cover.
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According to the report based on the study of penguin bones and shells, these 2 supermassive glaciers are positioned in a wide ocean basin shaped like a bowl, deepening towards the middle making the ice exposed to the warm currents of the ocean’s salt water.
Researchers fear that as these goliath-glaciers retreat further island, they could attain an irreversible collapse that could lead to a rise in sea level by almost a meter.
The reconstruction of glacier changes over 1000s of years was made possible by the ancient penguin bones and shells gathered by Scott Braddock, a glacial geologist in Hall’s lab.
Most of the samples of ancient penguin bones were collected on the coast of Lindsey 1 – one of many rocky islands dotted roughly 100 km from the Pine Island glacier.
As the last ice age was ending 12,000 years ago, Lindsey 1 would have been submerged below the surface, but as the massive glaciers melted displacing billions of metric tons of ice lowering the pressure on earth’s crust and helping the landmass rise gradually like a bed mattress (i.e. the islands rose a few millimeters every year).
The researchers measured the graph of the duration of the rise and the height of these shorelines to determine the amount of glacial ice lost to retreat.
They also carbon-dated penguin bones and shells to estimate the ages of the shorelines. The report revealed the oldest and highest shoreline formed 5,500 years ago.
Since then up to the last few decades, these islands have risen at a constant rate of about 3.5 mm per year which is way slower than the 20-40 mm per year current rate around these 2 glaciers.
This shows the ice is melting at the fastest rate because of us, after 1000s of years of a stable process.