probable-return-of-indian-oceans-ancient-climate-patterns

Context: A study in journal ‘science advances’ reported that formations like the El Niño of the Pacific Ocean could emerge in the Indian Ocean.

Background:

  • About 19,000-21,000 years ago, there was a peak of ice age conditions called the Last Glacial Maximum.
  • Around this time, ice-sheets covered North America and Eurasia, and sea-levels were much lower, with Adam’s Bridge exposed so that the Indian subcontinent and Sri Lanka were contiguous. 
  • By studying microscopic zooplankton called foraminifera, the team had published a paper in 2019 which first found evidence from the past of an Indian Ocean El Niño. 
    • Foraminifera builds a calcium carbonate shell, and studying these can tell us about the properties of the water in which they lived. 
    • The team using this property was able to reconstruct the sea surface temperature conditions of the past.

Findings of the Study:

  • Researchers analyzed simulations of this earlier climate and predicted that the current climate change could reawaken an ancient climate pattern of the Indian Ocean.
  • They found that this could be similar to the El Niño phenomenon of the Pacific Ocean which will bring more frequent floods and droughts to countries around the Indian Ocean. 
  • Look at the current warming scenario, the pattern could emerge by 2050.

Significance of the Study:

  • The study tells mankind that global sea-level is rising and glacial ice is melting today whereas the opposite was true for the Last Glacial Maximum.
  • The study highlights the probable changes in the Indian Ocean Dipole and the El Niño–Southern Oscillation owing to Global warming which will in turn strongly affect Indian Monsoon variability from year to year. 
    • This could bring more frequent droughts to East Africa and southern India and increased rainfall over Indonesia.

El Nino:

  • It is a climate cycle in the Pacific Ocean with a global impact on weather patterns. 
  • The cycle begins when warm water in the western tropical Pacific Ocean shifts eastward along the equator toward the coast of South America. 
  • Normally, these warm water pools near Indonesia and the Philippines.
  • Its most direct impacts are droughts in normally damp places in the eastern Pacific, such as parts of Indonesia and Australia, while normally drier places like the west coast of South America suffer floods.
  • But the changes affect the global atmospheric circulation and can weaken the Indian monsoon and bring rains to the western US.

Source: Guardian

Indian Ocean Dipole:

  • Sustained changes in the difference between sea surface temperatures of the tropical western and eastern Indian Ocean are known as the Indian Ocean Dipole or IOD. 
  • It is an irregular oscillation of sea surface temperatures in which the western Indian Ocean becomes alternately warmer (positive phase) and then colder (negative phase) than the eastern part of the ocean.
  • Positive Phase leads to better Indian Monsoon, Neutral has little effect and the negative phase weakens the monsoon and causes drought. 

Source: BBC

Source:

https://www.thehindu.com/sci-tech/science/when-the-indian-oceans-ancient-climate-patterns-return/article31934556.ece

Image Source: The Hindu