Climate Wire | Antarctic sea ice hit a record high in February. This is the smallest since satellites began monitoring it more than 40 years ago.
It’s the second year in a row and the fourth time since 2017 that the remote southern continent has reached record low ice levels.
A string of record-breakers may be a vestige of climate change. But scientists cannot say for sure.
Warming is already affecting Antarctica in other ways, such as accelerating ice loss from melting glaciers. However, sea ice in this region is more complex and does not always behave predictably.
“The Antarctic response to climate change is different than the Arctic,” said Ted Scambos, an Antarctic ice expert at the University of Colorado Boulder, in a statement. It may indicate that it is ultimately affecting floating ice around Antarctica, but it will take several more years to be sure.”
Until a decade ago, Antarctic sea ice was actually increasing for decades. This contrasts with Arctic sea ice, which is steadily declining as temperatures rise.
Then, around 2014, the Antarctic trend reversed sharply and sea ice began to decline rapidly. After hitting record lows in 2017 and 2018, it rebounded slightly and set new records in 2022 and 2023.
This may not be the first time Antarctic sea ice has flipped. A recent study used other forms of data from the last century to attempt to reconstruct sea ice trends from before satellite records began. This suggests that Antarctic sea ice may have been declining until her 1960s when it began to increase.
The reason is unknown.
and 2019 surveyNASA scientist Claire Parkinson says that the causes of the decades-long increase in ice at the end of the 20th century are “still unexplained.” Not enough time has passed to determine the cause of the decline.
A variety of factors, including natural variations in the Earth’s climate cycle, may be involved, she noted, and ice-related conditions can change over time. Some studies also suggest that the gradual healing of the Earth’s ozone hole, which has improved over decades, is altering the atmosphere in ways that could affect Antarctic winds and their impact on sea ice. This suggests that there is a possibility that
At the same time, the impacts of climate change are getting stronger and may have contributed to the recent decline.
Opposite
Factors other than human-induced warming often have a greater impact on the Antarctic than on the Arctic. One reason is that the two regions are physically very different.
The Arctic is very isolated, self-contained, and surrounded by land on all sides. Antarctica is essentially the opposite. She is one great landmass, surrounded by vast deep waters that merge with other seas.
Liping Zhang, a NOAA scientist who studies the Antarctic Ocean and Antarctic sea ice, said the Antarctic Ocean is so large and deep that it is “more resilient than other oceans to the effects of human-induced climate change.” It takes time,” he said. .
This means that strong natural climate variability can overwhelm human-induced warming signals. This may explain why historical trends in Antarctic sea ice are so perplexing compared to those in the Arctic Ocean.
Yet the impacts of climate change may catch up, if not yet. Zhang said it’s unclear exactly how long the process will take.
Very strong natural climate change could continue to overwhelm human-induced climate signals for some time, resulting in another sea ice inversion in the future. Antarctic sea ice may continue to decline indefinitely.
In fact, the recent decline “could be a result of climate change,” says Zhang. A combination of both atmospheric and oceanic factors, including warming in the Antarctic Ocean, likely caused her to hit a record low in February this year, she added.
“But we certainly don’t have enough data at the moment,” she added. “To better understand the observed changes and their implications for future behavior, we need to consider a variety of factors.”
If sea ice continues to decline, it could have far-reaching implications for Antarctica.
Sea ice acts as a kind of buffer between the ocean and the Antarctic ice sheet. As glaciers shrink, coastal glaciers become more susceptible to warming water, said Skambos of the University of Colorado Boulder.
“Shrinking sea ice extent means that ocean waves will beat the shores of giant ice sheets, further reducing ice shelves around Antarctica,” he said.
Reprinted from E&E News with permission of POLITICO, LLC. Copyright 2023. E&E News provides essential news for energy and environmental professionals.
