Arctic amplification: What is causing Arctic warming?

Source: The post is based on the article “What is causing Arctic warming?” published in The Hindu on 18^th August 2022.

Syllabus: GS 1 – geographical features and their location changes in critical geographical features (including water bodies and ice-caps).

Relevance: About the Polar and Arctic amplification.

News: A recent study points out 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. This is affecting the monsoons and climate conditions around the world.

What is Polar and Arctic amplification?

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.

Polar amplification: Any change in the surface air temperature and the net radiation balance tends to produce larger changes at the north and south poles. This phenomenon is known as polar amplification

Arctic amplification: The above changes are more pronounced in the northern latitudes than in the southern latitudes. This is known as Arctic amplification.

What are the causes of Polar and Arctic amplification?

Primary causes: Ice-albedo feedback, lapse rate feedback, water vapour feedback and ocean heat transport. Among these, the ice-albedo feedback and the lapse rate feedback are responsible for 40% and 15% of polar amplification respectively.

Ice-albedo feedback: Sea ice and snow have high albedo, implying that they are capable of reflecting most of the solar radiation compared to water and air. Global warming is resulting in diminishing sea ice. As the sea ice melts, the Arctic Ocean will be more capable of absorbing solar radiation.

Lapse rate feedback: The lapse rate or the rate at which the temperature drops with elevation decreases with warming.

What are the consequences of Arctic amplification?

The causes and consequences of Arctic amplification are cyclical, which means what might be a cause can be a consequence too.

Melting of Greenland ice sheet: Greenland’s old and thicker ice sheets are getting replaced by young and thinner ice sheets.

In 2019, the melting of this icesheet was the single biggest cause for the rise in the sea level, about 1.5 metres. If the Green land ice sheet melts completely, the sea level would rise by seven metres.

Note: The Greenlandic ice sheet holds the second-largest amount of ice, after Antarctica, and therefore it is crucial for maintaining the sea level.

Impact on biodiversity: The warming of the Arctic Ocean results in the acidification of water by changing the salinity levels. This impacts biodiversity, including the marine species and the dependent species.

Further, it also increases the amount of rainfall. This affects the availability and accessibility of lichens to the reindeer. This is causing widespread starvation and death among the Arctic fauna.

Impact on permafrost: 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.

What are the impacts of Arctic amplification on India?

Arctic ice and Indian monsoon: A study 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 India. 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.

Arctic ice and sea level rise: According to the World Meteorological Organization’s report, the 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.