Antarctic is Losing Huge Sea Ice Chunk

The planet is heating faster than governments can handle or address its effects.

According to scientists from WMO and EU’s Copernicus, July is the hottest month since records began. The month has also seen record-breaking heat waves worldwide, particularly in U.S. Southwest, Mexico, China, and the Mediterranean.

The scorching temperatures are linked to human-caused climate change mainly due to burning fossil fuels and releasing GHG emissions into the atmosphere. El Niño, which developed in May, also added to global temperatures.

The analysis published by the World Weather Attribution group found that the heat waves in North America and Europe were “virtually impossible” without climate change.

This time of the year, sea ice in the Antarctic is missing a chunk of sea ice bigger than Greenland or nearly as large as Argentina, astounding scientists.

While the northern hemisphere is experiencing the summer season, it is winter in the Antarctic, the opposite end of the globe, a time when floating sea ice should rapidly grow. But this year, the expansion of the sea ice has slowed significantly.

According to the National Snow and Ice Data Centre, “Arctic sea ice continues to decline at a near-average pace, with ice extent twelfth lowest in the satellite record. Antarctic sea ice, by contrast, is growing at far below-average rates and is at an unprecedently low level for this time of year relative to the 45-year data set.”

As of July, sea ice in the Arctic is about 1.31 million square kilometres (506,000 square miles) below the 1981 to 2010 reference period, and ice extent for July 17 is the twelfth lowest in the 45-year satellite record (Arctic Sea, 2023).

Ted Scambos, a glaciologist at the University of Colorado Boulder, told CNN that based on the significant amount of ice missing, “it’s clearly telling us that the system has changed”.

The Antarctic’s remoteness makes it challenging for scientists to understand how it responds to climate change. But since 2016, they observed a steep downward trend. Scientists have discovered that the Thwaites Glacier, an ice mass the size of Florida on the west side of the Antarctic, is melting. Scientists dub the glacier the “Doomsday Glacier” because of the consequences the melting will have on sea level rise and accelerating global warming.

CSIRO Fellow and Research Team Leader Dr Steve Rintoul said while there is some annual variation in ice coverage, this year’s records are the lowest in the 40 years since records started.

Sea ice forms when the ocean’s surface freezes, but in February 2023, sea ice around Antarctica reached the lowest extent ever observed at 1.79 million square kilometres since the start of the satellite record in 1979.

What controls how much ice is formed is a delicate interplay between the atmosphere and oceans.

“The factors that influence sea ice include winds from north to south are stronger than usual, which pushes sea ice towards Antarctica and restricts how far sea ice spreads. The warmer water means there is less sea ice, and even things like melting the surface melt can alter sea ice forming,” Rintoul said (Chung, 2023).

Melting from the bottom

A study published in Nature in February 2023 finds that different processes drive the rapid retreat of the Thwaites Glacier. Researchers have drilled a narrow hole through the ice to lower a remote-operated vehicle, Ice Fin and found that the glacier is melting fast on its underside cracks and crevices.

A first look at the glacier’s underbelly, hundreds of meters below sea level, researchers find that melting occurs within massive cracks called basal crevasses that open up the bottom of the glacier. This part of the ice is vulnerable to warm, salty ocean currents that hug the seafloor. 

A tiny quantity of melting at these vulnerable spots could inflict enormous structural damage on the glacier, according to researchers who report in two papers published in Nature on 15 February. 

Even a small amount of melting at these weak spots could inflict a disproportionately large amount of structural damage on the glacier, the researchers report in two papers published February 15 in Nature:

• Suppressed basal melting in the eastern Thwaites Glacier grounding zone
• Heterogeneous melting near the Thwaites Glacier grounding line

Scientists estimate that sea levels could rise by around 10 feet if the Thwaites collapse completely and will impact coastal communities worldwide.

Consequences of sea ice melt

Sea ice disappearance exposes coastal ice sheets and glaciers to wavers and warm ocean waters, increasing their chances to break off or melt.

Lack of sea ice impacts wildlife, including krill, on which many of the region’s whales feed, and penguins and seals that rely on them for feeding or resting.

Sea ice reflects as much as 90% of solar radiation, and its disappearance will expose the dark ocean surface, allowing them to absorb more of the sun’s energy, causing them to heat up and increase temperatures further.

The disappearance leaves coastal ice sheets and glaciers exposed to waves and warm ocean waters, making them more vulnerable to melting and breaking off.