Strong ice melt
Antarctic sea ice loss hits new record
The La Niña weather phenomenon apparently plays a major role in the strong ice melt at the South Pole
© Liu Shiping/DPA
The ice at the North Pole is melting rapidly as a result of climate change, while it has tended to increase slightly at the South Pole for decades. Suddenly, however, the scope there is also shrinking more than ever before.
Ice alert in Antarctica: This year, sea ice at the South Pole has fallen to its lowest level since records began in the late 1970s. The Feb. 25 record is the second sharp decline in ice cover in just five years, Chinese researchers from Sun Yat-sen University in Guangzhou and the Laboratory of Southern Oceanography in Zhuhai report in the journal Advances in Atmospheric Sciences. Although they have investigated ocean currents and weather phenomena behind the melt, they are still puzzled.
While the ice in the Arctic is rapidly receding due to global warming, the ice in the Antarctic has been growing slightly by one percent every decade since measurements began – albeit with regional and year-to-year differences. After a sharp decline had already been determined in 2017, researchers registered this anomaly again at the end of summer in the southern hemisphere at the end of February: For the first time since satellite recordings began in 1978, the extent of the Antarctic ice fell to less than two million square kilometers. It was around 30 percent lower than the average between 1981 and 2010.
Thin ice sheet
There was also an unusually thin ice sheet in the Amundsen and Bellinghausen Seas and in the Weddell Sea, among other places. In an effort to understand these complicated changes, the scientists analyzed the behavior of sea ice between 1979 and 2022. Among other things, they studied the dynamics of current transport and thermodynamic processes such as freezing and melting in the sea.
The analyzes led the scientists particularly to the Amundsen Sea. “All of these atmospheric effects originate from the intensity and location of the Amundsen Sea Depression (ASL) and ocean warming,” notes the team, looking at this center of atmospheric depression over the deep south of the Pacific Ocean.
La Niña plays an important role
The low point in sea ice this February also coincided with the La Niña weather phenomenon. At La Niña, strong winds push warm surface water from South America to Indonesia, among other things. This has repercussions in many regions of the world. The condition of a belt of strong westerly winds also played a role. Both phenomena reinforce the depression in the Amundsen Sea (ASL). The scientists write that the consequences of such events for Antarctica still need to be researched further.
The climate change service of the EU program Copernicus had already reported that the extent of the Antarctic sea ice measured daily had reached its lowest level since records began in February.