Record Low Global Sea Ice Cover

Sub: Geo

Sec: Climatology

Why in News

The global sea ice cover has reached a record low, raising concerns about climate change and its broader environmental consequences. Over the five days leading up to February 13, the combined extent of Arctic and Antarctic Sea ice dropped to 15.76 million sq km, breaking the previous record of 15.93 million sq km observed in January-February 2023.

What is Sea Ice?

Sea ice refers to the floating ice found in the polar regions, which expands in winter and melts during summer. Unlike icebergs, glaciers, ice sheets, and ice shelves that originate on land, sea ice forms directly on the ocean surface.
Sea ice helps regulate the Earth’s temperature by trapping heat within the ocean, preventing it from warming the atmosphere.

Extent of the Decline:

The Arctic is currently experiencing its lowest recorded sea ice extent for this time of the year.
Between 1981 and 2010, the minimum Arctic Sea ice extent (September) declined at a rate of 12.2% per decade (NASA data).
Until 2015, Antarctic Sea ice exhibited a slight increase in extent.
Between late 2014 and 2017, the Antarctic lost approximately 2 million sq km of sea ice—an area about four times the size of Spain (Copernicus Marine Service data).
In 2023, Antarctic Sea ice reached historically low levels, over 2 million sq km below normal—about ten times the size of the UK.
While the extent in 2024 showed some recovery compared to 2023, it was still 1.55 million sq km below the 1981-2010 average maximum extent.

Causes Behind the Decline:

Higher temperatures accelerate the melting of sea ice, particularly in the Antarctic, where warmer air and water towards the end of the southern hemisphere summer (December–February) intensified ice loss.
Unlike the Arctic, where sea ice is surrounded by continents, Antarctic Sea ice is more mobile and thinner, making it more vulnerable to strong winds that break it apart.
The Hudson Bay in northeastern Canada experienced a delay in freezing due to unusually warm ocean temperatures, which took longer to cool.
Storms in regions like the Barents Sea (near Norway and Russia) and the Bering Sea (between Alaska and Russia) contributed to breaking up the Arctic ice.
Over the years, Arctic ice has become increasingly thin and fragile, making it more susceptible to breaking under storm conditions.
Areas such as Svalbard, Norway, experienced unusually high air temperatures, further accelerating ice loss.

Implications of Declining Sea Ice:

Sea ice has a high albedo (reflectivity), meaning it reflects sunlight back into space. Reduced sea ice exposes more ocean surface, leading to increased absorption of solar radiation, which further warms the region.
Melting sea ice releases freshwater into the ocean, reducing salinity and surface water density. This weakens the ocean overturning circulation, affecting global climate patterns.
A slowdown in ocean circulation impacts the marine food chain, affecting species dependent on ocean currents for nutrients.
Ice shelves, which help stabilize ice sheets, become more unstable due to warmer waters and reduced ice cover.