While the Northern Hemisphere is experiencing record heat waves, Antarctica is breaking its own terrifying climate record. Sea ice on the continent has reached unprecedentedly low levels for this time of year, and scientists are trying to figure out why.
Normally, Antarctic sea ice shrinks to its lowest level by the end of February during the continent’s summer season, and then builds up again during the winter. This year, however, sea ice has not returned to expected levels and is at its lowest level since observations began 45 years ago. In mid-July, sea ice extent was 2.6 million square kilometers below the 1981-2010 average, nearly equal to the area of Argentina or the combined area of Texas, California, New Mexico, Arizona, Nevada, Utah and Colorado.
Some scientists call the phenomenon exceptional, occurring only once in millions of years. But glaciologist Ted Scambos of the University of Colorado at Boulder says it’s useless to talk in such terms because the system has changed. “It doesn’t make sense to talk about the probability of things happening the way they used to; it clearly tells us that the system has changed,” he said.
Antarctica is a remote and complex continent, and unlike the Arctic, where sea ice has been steadily declining due to the climate crisis, sea ice in Antarctica has fluctuated from record highs to record lows in recent decades. It is therefore more difficult for scientists to understand how it responds to global warming. However, since 2016, scientists have seen a sharp downward trend.
Several factors contribute to the loss of sea ice, including the strength of westerly winds around Antarctica, which have been linked to increased pollution on the planet. “Warmer ocean temperatures north of the Antarctic Ocean boundary mixing with water that is normally somewhat isolated from the rest of the world’s oceans is also part of this idea of how to explain it,” Scambos said.
At the end of February this year, Antarctic sea ice extent reached its lowest level ever recorded at 691,000 square miles. Scambos said this winter’s unprecedented phenomenon could be indicative of long-term changes on the isolated continent. It is more than likely that we will not see the Antarctic system restored to what it was, say, 15 years ago for a very long period in the future, or perhaps “never.”