This photo taken on November 29, 2018 shows penguins on floating ice as seen from the Chinese research icebreaker Xuelong, also known as the Snow Dragon, on an area of floating ice in the Southern Ocean. The icebreaker is part of China’s 35th Antarctic Research Expedition.
Xinhua News Agency | Xinhua News Agency | fake images
Antarctic sea ice has been at record low levels for the past several months. That’s not a good sign for the planet, which has been reaching record temperatures in the past week, but it’s also not nearly as bad as the melting that’s been going on in the Arctic for decades.
Tracking sea ice, which is frozen seawater floating on the ocean surface near the poles, is one way climate scientists measure how warming the planet is.
“Sea ice is sensitive to warmer temperatures: a small change from temperatures just below to temperatures above freezing is the difference between ice and ocean. Therefore, it is an early indicator of changes in the environment”. Walt Meier, senior research scientist at the University of Colorado National Snow and Ice Data Centerhe told CNBC.
The two poles of the earth are warming at a faster rate than any other part of the planet, howard diamondthe manager of the climate science program at the US National Oceanic Atmospheric Administration’s Air Resources Laboratory told CNBC.
“The poles are warming at a faster rate of change than anywhere else on the planet; But the equator is still the warmest region on the planet, and as it continues to warm along with the rest of the planet, its rate of change is less than that of the poles,” Diamond told CNBC.
What the record low sea ice in Antarctica means
AntarcticaSpanning the South Pole, it is an ice-covered land mass, surrounded by sea ice and the Southern Ocean.
On February 21, sea ice in Antarctica set an all-time low for the second consecutive year, since 1979, which is the oldest that the records in the National Ice and Snow Data Center have.
Since then, the amount of sea ice has continued track to record low levels.
“We’ve had three record-breaking summers in recent years (2016/17, 2022 and 2023), plus the current winter growing season is unlike anything we’ve seen in our 45 years of continuous satellite observations.” Will Hobbs, physical oceanographer and co-director of the sea ice project for the Australian Antarctic Program Associationhe told CNBC. “That’s a very sudden change, as until 2015 Antarctic coverage was increasing, not decreasing like the Arctic.”
The blue line shows the amount of sea ice in Antarctica in 2023. Since about April, the amount of sea ice in Antarctica is the lowest that the previously recorded minimum, which was in 2022.
National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder (CU Boulder), part of the CU Boulder Cooperative Institute for Research in Environmental Sciences (CIRES)
Because the decline in Antarctic sea ice is new, it’s too soon to know exactly why this is happening, according to scientists who study sea ice flows at the poles.
“As for the ‘is this climate change?’ question, the scientific community is probably not ready to say that yet.” Will Hobbs, physical oceanographer and co-director of the sea ice project for the Australian Antarctic Program Associationhe told CNBC. It’s “the million-dollar question,” Hobbs said, and answering it “will keep us busy for a few more years.”
That said, it’s not good news.
“What we can say for sure is that this type of collapse was predicted, although not for a few decades, so the best case scenario is that we are getting a glimpse of the future of Antarctica,” Hobbs told CNBC. “The worst case scenario is that the ice doesn’t recover and the future came a few decades earlier than we expected and expected.”
Because sea ice floats, it doesn’t directly cause sea level rise, Hobbs told CNBC. Think of ice cubes melting in a glass of water.
But sea ice levels indirectly impact sea level rise. “Antarctic ice sheets, which could cause large sea level rise, are not sliding into the ocean on floating ice shelves, and they are melting,” Hobbs told CNBC. “Sea ice protects those ice shelves from being flexed and cracked by ocean waves, and it’s also a ‘shade’ that prevents the water in front of those ice shelves from heating up in the summer sunlight.”
Why Are Arctic Sea Ice Levels More Damning?
The Arctic is an ocean. covered by a layer of sea ice and surrounded by land. The amount of sea ice in the Arctic in June was 13th lowest on recordaccording to data from the National Snow and Ice Data Center.
“While Antarctica is more extreme right now, the Arctic has been more extreme for a long time. As I said, Antarctica had a record extent in 2014, the year of the record extent in the Arctic was 1979, the first year of record,” Meier told CNBC.
The blue line represents the sea ice in the Arctic in 2023. The red line shows the sea ice in 2012, which is the minimum on record.
National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder (CU Boulder), part of the CU Boulder Cooperative Institute for Research in Environmental Sciences (CIRES)
Because trends in sea ice have persisted longer and more data is available for the region, it is also more clearly attributable to global warming.
“Absolutely yes, we’ve known for a few years now, at least the last 10 to 15 years, that the loss of Arctic sea ice is unequivocally due to human-forced climate change,” Hobbs told CNBC.
The thickness of sea ice is one way to measure its age because sea ice gets thicker as it ages because it survives summer melt seasons and grows in winters, Meier told CNBC. Sea ice in the Arctic would tend to be between 10 and 13 feet thick, while in the Antarctic it has been closer to 3 to 6.5 feet thick. But most of the thickest, oldest ice has melted in the Arctic, and what remains is close to 6.5 feet thick.
“Despite the recent record low extent in Antarctica, the thickness has not changed much. Therefore, the subsurface change in Arctic sea ice is much more pronounced than the change in Antarctic sea ice. Meier told CNBC.
An aerial view of ice and melting pancakes on July 19, 2022, captured on a NASA Gulfstream V aircraft during an airborne mission with University of Texas scientists to measure melting of Arctic sea ice. New ICESAT-2 observations show a remarkable thinning of the Arctic sea ice in just three years. Over the past two decades, the Arctic has lost about a third of its winter sea ice volume, largely due to a decline in sea ice that persists for several years, called multi-year ice, according to a new study. The study also found that sea ice is likely thinner than previous estimates.
Kerem Yucel | Afp | fake images
And then there’s the land ice
In addition to sea ice, the poles have fairly large amounts of land ice.
The annual loss of land ice in the Arctic since 2002 has been 276 billion tons per year compared to 146 billion tons per year in the Antarctic, NOAA’s Diamond told CNBC. “They are both in the same direction down,” she said.
While sea ice does not directly contribute to sea level rise, melting land ice does.
“The melting of these ice sheets is accelerating rapidly, right now they lose about 400 billion tons of ice every year. This is enough ice to cover all of New York City with about 1,000 feet of ice, and that’s it’s just a year’s worth of ice loss,” Notz told CNBC.
The melting of land ice in some parts of the Antarctic ice sheet may be getting closer to a “tipping point,” Notz told CNBC.
“With just a little bit of additional warming, the loss of parts of the ice sheet could become unstoppable for many centuries or millennia to come, even if we manage to cool the climate again. This is because some processes within the ice sheet then they become self-accelerating, and increasingly independent of the warming that triggered the initial ice loss,” Notz said.
