Analysis of the latest satellite imagery shows that sea ice around Antarctica has reached a 40-year low. According to the National Snow and Ice Data Center at the University of Colorado Boulder, as of February 22, the ice cover around the Antarctic coast was approximately 1.94 million square kilometers, breaking the previous record low of 2.11 million square kilometers set in early March 2017.
Antarctic sea ice reaches record low, ocean warming only one reason
Marilyn N. Raphael, a UCLA geography professor who studies Antarctic sea ice, said warmer ocean temperatures are likely a factor, "but we'll be working over the next few months to identify other factors."
Antarctic sea ice extent varies greatly from year to year, but has generally increased very slightly since satellite observations began in the late 1970s. In contrast, the Arctic, which is warming three times faster than other regions, has seen its sea ice extent decrease by more than 10% per decade over the same period.
The two regions are very different. The North Pole and the Polar Circle are covered by the Arctic Ocean and surrounded by land. In the Southern Hemisphere, the South Pole and the Polar Circle are covered by the Antarctic continent and surrounded by the Southern Ocean.
While rapid warming in the Arctic is the primary driver of the decline in sea ice there, the impact of climate change on Antarctic sea ice is less clear.
Is global warming causing the reduction of Antarctic sea ice? Scholars: The relationship between the two is still unclear
Edward Blanchard-Wrigglesworth, a climate scientist at the University of Washington, said many scientists predict that global warming will eventually lead to a decrease in Antarctic sea ice. But at the moment, he said, "it's really hard to establish a relationship, especially with a single event like this."
Antarctic sea ice is influenced by many complex factors. Large-scale atmospheric patterns, often occurring far from the continent, local ocean currents and winds can all increase or decrease the extent of sea ice.
Dr. Wrigleysworth said some studies showed that strong El Niño events in 2015 and 2016, when sea surface temperatures in the tropical Pacific were above normal, led to a sharp decline in sea ice cover in 2016.
Ted Scambos, a senior researcher at the University of Colorado's Center for Earth Science and Observation, said warmer-than-normal sea surface temperatures in parts of Antarctica may be contributing to the current record low sea ice.
Raphael said the record low sea ice levels could also be linked to winds, particularly in the Amundsen Sea, west of the Antarctic continent. She said the low pressure that forms annually over the ocean was particularly strong this year, creating stronger winds that could push more ice northward into warmer waters, accelerating melting.
Source: Environmental Information Center (https://e-info.org.tw/node/233492)
