Sudden changes taking place in Antarctica “will affect the world for future generations”
Antarctic has long been considered a distant and immutable environment. No more.
The continent covered with ice and the surrounding southern ocean undergo sudden and alarming changes. Sea ice cream is quickly narrowed, the floating glaciers known as ice plateaus melt faster, the glacial caps line the continent approach shift points and vital ocean currents show signs of slowing down.
Published today in nature, our new research shows that these sudden changes are already underway – and likely to intensify considerably in the future.
Several authors of this article have witnessed these surprising changes during work on the field on ice. These changes spend bad news for fauna, both emblematic and less known. But changes will reach much further. What is happening in Antarctica at the moment will affect the world for future generations, from the increase in sea level to extreme changes in the climate system.
What is a brutal change?
Scientists define a brutal change as a climate or environmental change which takes place much faster than expected.
What makes sudden changes so worrying is that they can increase. For example, the fusion of sea ice allows oceans to warm up faster, which melts more sea ice. Once triggered, they can be difficult or even impossible to reverse significant time scales for humans.
In relation: Scientists discover that the giant rivers lost for a long time that crossed Antarctica 80 million years ago
If it is common to assume that increasing global warming will result in a progressive change, we see something very different in Antarctica. In recent decades, the Antarctic Environment has had a much more silent response to global warming caused by humans compared to the Arctic. But about ten years ago, sudden changes began to occur.
The narrowing of sea ice brings a cascade change
The natural Antarctic systems are closely intertwined. When a system is unbalanced, it can trigger cascade effects in others.
Sea ice around Antarctica was radically Since 2014. The extent of sea ice has now been shrinking at double the arctic sea ice rate. We have found that these deployment changes are unprecedented – far from the natural variability of past centuries.
The implications are large. Sea ice has a reflection, high album Surface that reflects heat to space. When there is less sea ice, more heat is absorbed by the darker oceans. Penguins emperors and other species depositing on sea ice for habitat and reproductive face real threats. Less sea ice also means that Antarctic’s ice shelves are more exposed with waves.
Vital ocean currents slow down
The fusion of ice actually slows down the deep circulation of the ocean around the Antarctica. This system of deep currents, known as the antarctic reversal circulation, plays an essential role in regulating the earth climate by absorbing carbon dioxide and distributing heat.
In the northern hemisphere, the circulation of meridian reversal of the Atlantic is faced with a to slow down.
We now observe a similar risk in Austral ocean currents. Changes to the antarctic reversal circulation can take place at Twice the rate of the most famous counterpart in the North Atlantic.
A slowdown could reduce the amount of oxygen and carbon dioxide Absorb of the ocean and leave vital nutrients at the seabed. Less oxygen and less nutrients would have major consequences for marine ecosystems and climate regulation.
Merger generations
The western antarctic skewer as well as certain regions of eastern Antarctica are now lose ice cream and contribute to elevation of sea level. Loss of ice has increased by six times since the 1990s.
The western antarctic ice cap alone has enough ice to increase the world level of the sea by more than five meters – and Scientists warn We could approach the point where this ice cap could collapse even without substantial warming, although this can take centuries to millennia.
These huge glacial caps represent the risk of a global change point. They contribute the greatest uncertainty to the projections of the future increase in sea level because we do not know how fast they could collapse.
In the world, at least 750 million people Live in low zones near the sea. The increase in sea level threatens coastal infrastructure And communities worldwide.
Threatened fauna and ecosystems
Biological systems of Antarctica also undergo sudden changes. Ecosystems under the sea And on earth are reshaped by warming temperatures, unreliable ice conditions and human activity providing pollution and The arrival invasive species.
It is essential to protect these ecosystems through the Antarctic Treaty, in particular the creation of protected land and sea areas and to restrict certain human activities. But these conservation measures will not be sufficient to ensure that emperors penguins and leopard seals survive. This will require decisive global action to reduce greenhouse gas emissions.
What future?
Antarctica is often considered a symbol of isolation and permanence. But the continent is now evolving with a disturbing speed – much faster than scientists had planned it.
These sudden changes come largely from the additional heat trapped by decades of uncontrolled greenhouse gas emissions. The only way to avoid other sudden changes is to reduce emissions quickly enough to keep warming Also almost 1.5 ° C as possible.
Even if we succeed, many changes have already been set in motion. Governments, companies and coastal communities must prepare for a future of brutal change. What is happening in Antarctica will not stay there.
The issues could not be higher. The choices made now will determine whether we are faced with a future of worsening of impacts and an irreversible change or resilience managed with changes already locked up.
This published article is republished from The conversation Under a creative communs license. Read it original article.
