Antarctica’s Deep-Winter Heatwave
Context:
For the second consecutive year, Antarctica is experiencing a record-breaking heatwave during its winter season, with average ground temperatures 10°C above normal and reaching 28°C higher on some days.
The polar vortex is a large area of low pressure and cold air surrounding both of the Earth’s poles. It always exists near the poles, but weakens in summer and strengthens in winter. The term “vortex” refers to the counter-clockwise flow of air that helps keep the colder air near the Poles.
Reasons for a Heatwave:
- Higher temperatures are mainly a consequence of the weakening of the polar vortex.
- The vortex usually remains strong and stable during winter in the southern hemisphere — keeping cold air trapped over Antarctica and not letting hot air come in — but it has been disturbed this year by large-scale atmospheric waves (periodic disturbances in the fields of atmospheric variables).
- Due to this, the vortex released trapped cold air, and opened the door for warmer air to enter the region.
- As this warmer air travelled downwards from the upper atmosphere, it caused an increase in temperatures.
- Several other factors including the reduction of the extent of the Antarctic sea ice, could also be at play.
- In June, the extent of Antarctic sea ice was the second-lowest ever for that time of year — a little more than the extent recorded in June 2023, the lowest ever.
- According to a 2023 study published in the journal Nature Climate Change, the continent is likely warming at a rate of 0.22 degrees Celsius to 0.32 degrees Celsius per decade — almost twice as fast as the rest of the world.
- The Intergovernmental Panel on Climate Change (IPCC), has estimated that the Earth as a whole is warming at the rate of 0.14-0.18 degrees Celsius per decade.
Sea ice plays a crucial role in keeping temperatures down in the polar regions, as its bright, white surface reflects more sunlight (solar energy) back to space than liquid water.
Sea ice also ensures that the air remains cool by acting as a barrier between the cold air and the relatively warmer water below.
The possible fallouts:
- It will lead to further losses of the Antarctic Ice Sheet (the world’s other major ice sheet is the Greenland Ice Sheet) that can potentially raise global sea levels by hundreds of feet.
- According to a 2019 study published in the journal PNAS (Proceedings of the National Academy of Sciences), Antarctica has already lost 280% more ice mass in the 2000s and 2010s than it lost in the 1980s and 1990s.
- The Antarctic Ice Sheet, covering 98% of Antarctica and containing over 60% of the world’s freshwater, has the potential to drastically alter the global landscape if it were to fully melt.
- According to the Antarctic and Southern Ocean Coalition, a sea level rise of just a few feet could displace approximately 230 million people currently living within 3 feet of high tide.
- Rising temperatures will also impact the global ocean circulation system, which regulates climate by storing and transporting heat, carbon, nutrients, and freshwater worldwide.
