Antarctic Glaciers

Scientists warn: accelerated melting of Antarctic ice confirms worst-case scenario

By sounding the alarm about the climate, scientists can make some of us think of the fable of the boy and the wolf. Yet studies are multiplying and repeating themselves: all the scenarios lead to a worsening that is unfolding before our very eyes. One latest research revealed by the Washington Post is particularly alarming: the melting of Antarctic ice is seriously disrupting ocean circulation and leading us straight to a world of rapidly rising seas and super storms. This diagnosis was confirmed yesterday by a consortium of researchers who noted an increase in wave height on the west coast of Europe.
Coceans and the melting of the Antarctic ice pack have long been the focus of scientific attention. Computers in the world's best labs are calculating their models and trying to predict developments. This was the case two years ago with the model established by former NASA climatologist James Hansen and several of his colleagues. Their simulation The computer study concluded that the nature of ocean water was changing, in particular due to the melting of glaciers and a rapid rise in sea levels. This scenario met with scepticism from many other climatologists.
News research conducted in the Antarctic have just released their findings. They are not based on a computer simulation but on real observations. They describe an alarming phenomenon: the melting of Antarctic glaciers is cooling the ocean around them. And this, in turn, is blocking a process in which cold, salty ocean water sinks below the sea surface in winter, forming "...a new ocean...". the densest water on earth "in the words of the study's lead author, Alessandro Silvano, a researcher at the University of Tasmania in Hobart, Australia. This so-called Antarctic bottom water has stopped forming in two key areas: the west coast and the coast around the huge Totten Glacier in East Antarctica.

Infernal machine

These two regions are melting the fastest, leading to a process that is a vicious circle: surface water fed by melting glaciers fails to sink into the deep ocean and releases the circulation of a layer of warmer water at depth. This water flows across the continental shelf and into the base of the glaciers. This warm water then dramatically accelerates the melting of glaciers and all the large ice sheets.
Washington Post explains that the melting of Antarctic glaciers is triggering a " feedback loop "in which this melting, through its effect on the oceans, triggers even more melting. This phenomenon creates a stratification of the ocean column; cold freshwater is trapped at the surface while warmer water circulates below. This lower layer penetrates underneath the glaciers and the pack ice melts them, creating even more fresher water trapped at the surface. A veritable infernal machine.
What we found is not just a modeling study, but it's something we've observed in the real ocean "said Alessandro Silvano, who led the research with colleagues from several other institutions in Australia and Japan. « Our study shows for the first time real evidence of this mechanism. Our study shows that it is already happening. "
According to Matthew Long, an oceanographer at the National Center for Atmospheric Research, this study " is part of a large body of literature that shows the warming and cooling of the deep ocean in the southern hemisphere. ». He goes on to say: " The fact that we are seeing a constant warming and cooling indicates that the processes we are predicting for the next century are already under way. ".

All the oceans are breaking apart

This study is part of a growing body of evidence suggesting that the world's oceans are changing, and that the pace of change is accelerating. The change in the circulation system of currents in the Southern Hemisphere is similar to that observed in the Northern Hemisphere with the slowing of the Atlantic overturning circulation.

READ UP : The Gulf Stream is breaking apart at breakneck speed. It's very bad news.

Until now, the North Atlantic was thought to be the area most vulnerable to global warming. However, it is now being observed that the phenomenon is also reproducing itself in the Antarctic. The consequences of these disruptions could be massive. Sea level rise is one that affects us all.
Climatologists have been telling us for years about sea level rise, which they put in millimetres a year, which doesn't really speak to the public mind. What the public perceives better is the increase in storms on the Atlantic coast and the increase in wave power.
A study has just been carried out by scientists from the Centre National de la Recherche Scientifique (CNRS) in France, the University of Bordeaux and the University of Plymouth. Their work, which was accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union, focused on measuring wave heights in extreme weather conditions. They found that levels off the Irish coast, for example, have increased by 25 mm/year over the past 70 years, an average increase of 1.7m.

Alert signal

The findings of this study should serve as a warning signal for coastal scientists and managers seeking to predict future wave heights and take action to protect coastal communities throughout Western Europe.
Bruno Castelle, a senior scientist at the CNRS, said in a statement : " Wave heights during winter storms are the main factor affecting dune and cliff erosion, accounting for up to 80% of shoreline variability along exposed sandy coastlines. Thus, any increase in wave height and frequency of extreme storms will have a major impact on thousands of communities along the Atlantic coasts of Western Europe. This work and our other recent studies have shown that both are on the rise, which means that there is a real need to ensure that Europe's Atlantic coasts are protected from current and future storm threats. ".
The study used a combination of weather and hindcast wave forecasts, as well as actual data, to measure changes in wave heights and variability on coasts from Scotland in the north to Portugal in the south.
These analyses combine to encourage us to think seriously about reducing our vulnerability on exposed coasts and to adapt proactively to future scenarios.
Sources: Washington Post, University of Plymouth

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