Arctic warming

Context: On August 11, Finnish Meteorological Institute researchers published their study in the  Communications Earth & Environment journal, concluding that the Arctic is heating four times faster than the rest of the planet.

The warming is more concentrated in the Eurasian part of the Arctic, where the Barents Sea north of Russia and Norway is warming at an alarming rate — seven times faster than the global average.

What is Arctic amplification? What causes it?

• Global warming, expedited due to anthropogenic forces 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 vapour feedback and ocean heat transport are the primary causes.
• Sea ice and snow have high albedo 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 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 too.
• The Greenland ice sheet saw a sharp spike in the rate and extent of melting between July 15-17 this year.
• The unusual summer temperatures resulted in a melt of 6 billion tonnes of ice sheet per day, amounting to a total of 18 billion tonnes in a span of three days, enough to cover West Virginia in a foot of water.
• In 2019, Greenland ice melt 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 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.
• 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?

• The link between the changing Arctic and the monsoons in the subcontinent is growing in importance due to the extreme weather events the country faces, and the heavy reliance on rainfall for water and food security.
• A study titled ‘A possible relation between Arctic sea ice and late season Indian Summer Monsoon Rainfall extremes’ 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 — in September and October.
• The changes in the atmospheric circulation due to diminishing sea ice combined with the warm temperatures in the Arabian Sea contribute to enhanced moisture and drive extreme rainfall events.
• 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.

The Arctic amplification furthers the idea that “what happens in the Arctic does not remain in the Arctic” and can substantially affect tropical processes far south.

Source: The Hindu