Surprisingly, it was only in the mid-2010s that Antarctic sea ice was known. higher-less since satellite observations began -increased slightly but steadily in the years since 1979.
The recent expansion of Antarctic sea ice has been in stark contrast to what happened in the Arctic, an area that is now growing four times faster than the rest of the world and has been losing ice for decades. This is due to a phenomenon called Arctic amplification: The melting of the ice makes the sea water very dark or the land, which absorbs more solar energy than the white ice, which leads to higher temperatures.
The Antarctic is a different beast: It is a cold continent surrounded by open ocean, while the Arctic is a sea of floating ice surrounded by land, such as Russia, Alaska, and northern Canada. Antarctica’s ice is trapped in a certain way by the strong, cold ocean currents that surround the continent. Also, the surface of Antarctica is very high, providing additional cooling.
Antarctica’s sea ice—which is made up of frozen sea water—is very different from the continental ice and shelves. The snow is on the ground, and it can be thousands of feet. It becomes like ice when it starts to float on coastal waters. Although Antarctica’s sea ice and shelves have been declining as the planet warms, the continent’s sea ice is seasonal, melting and shrinking significantly between winter and summer.
Dumping sea ice will not increase the sea level, just as melting ice floating in a glass of water will not cause the glass to overflow. (The ice has already begun to retreat.) But the sea ice is what helps to protect the Antarctic ice from destruction, and the water can rise significantly when the water breaks. If it melts completely, Thwaites Glacier, also called Doomsday Glacier, could add 10 meters to the sea level. Sea ice protects the Thwaite and other glaciers because it acts as a buffer for the ice, absorbing the forces of wind and waves that would otherwise erode it. They also cool air passing over coastal waters, which in turn prevents the melting of ice.
This year, the coast of West Antarctica has been very ice free. Maksym said: “It is an area where climate scientists are very concerned about what climate scientists can do to help with the growth of the world’s ice sheets.” “This year, we’re not seeing any sea ice in this area, which I think is the first time that’s happened. So there are some previous studies that have shown that if you remove the sea ice, you lose the effect, and that can accelerating the breaking of the ice.”
But that’s not all that will happen around the world because of the sea ice: When the sea water freezes into ice, the ice that is about to disappear sinks to the bottom of the ocean, creating deep waves that rush away from Antarctica. The less sea ice, the weaker those waves. “This will affect how the oceans distribute energy, and ultimately will affect global climate,” said UCLA geographer Marilyn Raphael, who studies the area. What happens in Antarctica does not stay in Antarctica.
