Rapid Collapse Of 2 Melting Glaciers Could Bury Shorelines Around The World
We may be headed for an ice apocalypse which could result in the flooding of coastal cities before the end of this century.
There are two warnings about melting ice and rising oceans: one is by land, the other, by sea. But it’s ice sheets on land, not icebergs in the ocean, that are the biggest contributors to sea level rise.
Land ice includes mountain glaciers and ice sheets, covering Greenland and Antarctica. These giant blocks of ice are melting and the water is flowing rapidly into the oceans. Think of it like adding water to an already full glass — it soon overflows.
Melting sea ice has no impact on sea level rise because it’s already floating in the ocean.”
Grist reports on two of the largest and fastest-melting glaciers in Antarctica which “hold human civilization hostage.” There’s no doubt this ice will melt as the world warms.
The vital question is when… Together, they act as a plug holding back enough ice to pour 11 feet of sea-level rise into the world’s oceans — an amount that would submerge every coastal city on the planet… Each new iceberg that breaks away exposes taller and taller cliffs.
In the past few years, scientists have identified marine ice-cliff instability as a feedback loop that could kickstart the disintegration of the entire West Antarctic ice sheet this century — much more quickly than previously thought. Minute-by-minute, huge skyscraper-sized shards of ice cliffs would crumble into the sea, as tall as the Statue of Liberty and as deep underwater as the height of the Empire State Building.
The result: a global catastrophe the likes of which we’ve never seen… When [land-based ice] falls into the ocean, it adds to the overall volume of liquid in the seas. Thus, sea-level rise…. All this could play out in a mere 20 to 50 years — much too quickly for humanity to adapt…
A lot of this newfound concern is driven by the research of two climatologists: Rob DeConto at the University of Massachusetts-Amherst and David Pollard at Penn State University. A study they published last year was the first to incorporate the latest understanding of marine ice-cliff instability into a continent-scale model of Antarctica.
Instead of a three-foot increase in ocean levels by the end of the century, six feet was more likely, according to DeConto and Pollard’s findings. But if carbon emissions continue to track on something resembling a worst-case scenario, the full 11 feet of ice locked in West Antarctica might be freed up, their study showed.
With marine ice cliff instability, sea-level rise for the next century is potentially much larger than we thought it might be five or 10 years ago
If sea levels rise by six feet, “around 12 million people in the United States would be displaced, and the world’s most vulnerable megacities, like Shanghai, Mumbai, and Ho Chi Minh City, could be wiped off the map.”
Antarctica is a giant landmass—about half the size of Africa—and the ice that covers it averages more than a mile thick. Before human burning of fossil fuels triggered global warming, the continent’s ice was in relative balance: The snows in the interior of the continent roughly matched the icebergs that broke away from glaciers at its edges.
Now, as carbon dioxide traps more heat in the atmosphere and warms the planet, the scales have tipped.
A wholesale collapse of Pine Island and Thwaites would set off a catastrophe. Giant icebergs would stream away from Antarctica like a parade of frozen soldiers. All over the world, high tides would creep higher, slowly burying every shoreline on the planet, flooding coastal cities and creating hundreds of millions of climate refugees.
All this could play out in a mere 20 to 50 years—much too quickly for humanity to adapt.