In a worst case scenario, the melting of the entire Antarctic Ice sheet would lead to a rise of sea levels of 57 meters. But with a surface of 12,1 millions Km² that rises of 2,9% every decade since the 1980’s, the Antarctic ice doesn’t really seem to suffer from the climate change. Or does it ?
The Antarctic case shows how complex the climate issue is. Indeed, if the surface of the Ice sheet rises, its volume is dramatically diminishing.
All the Antarctic parts do not react the same way to climate change. In the West, the ice sheet is breaking apart while in the South and the East, it keeps growing. But how can such a phenomenon be explained ?
Jinlun Zhang from the University of Washington, brought an explanation to the current evolution of the Antarctic Ice sheet. According to him, stronger westerly winds around the South Pole can explain 80% of the Antarctic sea ice volume increase in the past three decades. The polar vortex that swirls around the North Pole is not just stronger than before, it has also more convergence meaning it shoves the ice together to cause ridging. The Southern Ocean also becomes colder because of the ice melting which causes runoff. These cold waters boosts the spread of thin ice around Antarctica.
There are land ice and sea ice. Land ice is the result of thousands of years of snow that has become ice over time. Sea ice is made of salted water, it expands during winter months and disappears almost completely in summer.
In Antarctica, the sea ice raises while the land ice reduces. A recent study proved that every year, Antarctica loses between 100 and 300 Giga tons of ice. It has to be reminded that the melting of 360GT per year causes the rise of sea levels of 1mm.
So the Antarctic’s surface increases but its volume decreases !