GS Paper 1
Syllabus: Important Geophysical Phenomena such as cyclones etc
Source: IE
Direction: While the earlier article explained the phenomena of bomb cyclones, today’s article highlights the probable reasons behind such an extreme weather event.
Context: In a report published in The Washington Post, scientists have once again started to discuss if the rising temperatures of the Arctic are responsible for extremely cold conditions in the US and other areas of the Northern Hemisphere.
Background:
- A deadly blizzard (bomb cyclone) has gripped the US, leading to the death of more than 60 people as of now and the complete disruption of normal life.
- A similar chain of events took place back in 2021 when Texas witnessed a deadly cold storm that killed 246 people.
The findings of the study:
- The study largely focused on the polar vortex, which is a mass of cold, low-pressure air that consistently spins over the Arctic region counter-clockwise, just like a hurricane does.
- Usually, the polar vortex remains strong and compact, meaning the mass of frigid air stays at the North Pole.
- But sometimes it weakens (like a wobbling top) and expands to influence the jet stream – an area of fast-moving air high in the atmosphere that surrounds the polar vortex.
- Once the jet stream is impacted, the cold polar air finds its way towards the mid-latitude regions.
- The polar vortex has been expanding more than twice as frequently in recent years, owing to the steadily warming Arctic.
- The melting sea ice in the Barents and Kara seas north of Russia and Scandinavia and increasing Siberian snowfall create larger and more energetic atmospheric waves that ultimately stretch the polar vortex
- This has resulted in extreme winter weather in the US and other places.
Earlier studies:
- The debate started in 2012 after research showed that the warming of the Arctic was reducing the temperature difference between the polar and tropical regions.
- This has weakened the jet stream, allowing the southward movement of frigid air.
Conclusion: Despite some evidence, the scientific community still has conflicting opinions about its claim. Hence, more data is required to determine whether and where warming is weakening the jet stream.
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