Combined Antarctic-Arctic Sea ice extent lowest

Combined Antarctic-Arctic Sea ice extent lowest

Subject :Environment

Section: Climate Change

Context: This year, the combined sea ice extent of the Antarctic and Arctic was also the lowest-ever for January, said the US National Snow and Ice Data Center (NSIDC).

More on the News:

• January 2023 ended as the seventh warmest globally, and was 0.25 degree Celsius (°C) warmer than the average (the period of 1991-2020), according to the latest report released by the European Centre for Medium-Range Weather Forecasts (ECMWF).
• The Arctic is warming more than twice as fast as the global average.

What is Arctic amplification? What causes it?

• Global warming, the long-term heating of the earth’s surface, expedited due to anthropogenic forces or human activities since pre-industrial times and has increased the planet’s average temperature by 1.1 degrees Celsius. While changes are witnessed across the planet, any change in the surface air temperature and the net radiation balance tend to produce larger changes at the north and south poles. This phenomenon is known as polar amplification; these changes are more pronounced at the northern latitudes and are known as the Arctic amplification.
• Among the many global warming-driven causes for this amplification, the ice-albedo feedback, lapse rate feedback, water vapor feedback and ocean heat transportare the primary causes. Sea ice and snow have high albedo (measure of reflectivity of the surface), implying that they are capable of reflecting most of the solar radiation as opposed to water and land.
• In the Arctic’s case, global warming is resulting in diminishing sea ice. As the sea ice melts, the Arctic Ocean will be more capable of absorbing solar radiation,thereby driving the amplification.
• The lapse rate or the rate at which the temperature drops with elevation decreases with warming. Studies show that the ice-albedo feedback and the lapse rate feedback are responsible for 40% and 15% of polar amplification respectively.

What are the consequences of Arctic warming?

• The causes and consequences of Arctic amplification are cyclical, what might be a cause can be a consequence
• The Greenland ice sheet is melting at an alarming rate, and the rate of accumulation of sea ice has been remarkably low since 2000, marked by young and thinner ice replacing the old and thicker ice sheets.
• Greenlandic ice sheet holds the second largest amount of ice, after Antarctica, and therefore it is crucial for maintaining the sea level. In 2019, this was the single biggest cause for the rise in the sea level, about 1.5 metres. If the sheet melts completely, the sea level would rise by seven metres, capable of subsuming island countries and major coastal cities.
• The warming of the Arctic Ocean and the seas in the region, the acidification of water, changes in the salinity levels, is impacting the biodiversity, including the marine species and the dependent species.
• The warming is also increasing the incidence of rainfall which is affecting the availability and accessibility of lichens to the reindeer.
• The Arctic amplification is causing widespread starvation and death among the Arctic fauna.
• The permafrost in the Arctic is thawing and in turn releasing carbon and methane which are among the major greenhouse gases responsible for global warming.
• Experts fear that the thaw and the melt will also release the long-dormant bacteria and viruses that were trapped in the permafrost and can potentially give rise to diseases. The best-known example of this is the permafrost thaw leading to an anthrax outbreak in Siberia in 2016, where nearly 2,00,000 reindeer succumbed.

What is the impact on India?

• A study titled ‘A possible relation between Arctic sea ice and late season Indian Summer Monsoon Rainfall extremes’published in 2021 by a group of Indian and Norwegian scientists found that the reduced sea ice in the Barents-Kara sea region can lead to extreme rainfall events in the latter half of the monsoons.
• The changes in the atmospheric circulationdue to diminishing sea ice combined with the warm temperatures in the Arabian Sea contribute to enhanced moisture and drive extreme rainfall.
• According to the World Meteorological Organization’s report, ‘State of Global Climate in 2021’, sea level along the Indian coast is rising faster than the global average rate. One of the primary reasons for this rise is the melting of sea ice in the Polar Regions, especially the Arctic.