Arctic Amplification

Q. Why is this in news?

A. Finnish researchers have found that the Arctic is heating four times faster than the rest of the planet.

Q. Why is Arctic warming faster?

A. 

• The warming is 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.
• Other studies indicate that the Arctic amplification is four times the global rate.

Q. What is Arctic Amplification?
A . 

• Global warming has hastened 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.

Q. What causes amplification?

A. 

• 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 (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 rate at which the temperature drops with elevation i.e. lapse rate 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.

Q. What do the previous studies say?

A. 

• The extent of Arctic amplification is debated, as studies show various rates of amplification against the global rate.
• Studies have shown that the Arctic was warming at twice the global rate prior to the beginning of the 21st century.
• Already the Arctic surface air temperature has likely increased by more than double the global average over the last two decades.

Q. What are the consequences of Arctic warming?

A. 

• The causes and consequences of Arctic amplification are cyclical — what might be a cause can be a consequence too.
• The Greenland ice sheet is melting at an alarming rate, and the rate of accumulation of sea ice has been remarkably low since 2000.
• This is also 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.

Q. What are the Visible impacts?

A. 

• 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, are 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.

Q. What is the impact on India?

A.

• In recent years, scientists have pondered over the impact the changing Arctic can have on the monsoons in the subcontinent.
• The link between the two 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 says that 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.