Current Affairs

Issue

Researchers have analysed simulations of past climate in the Indian ocean and predicted that the ongoing climate change could reawaken an ancient climate pattern.

 

Background

About 19,000-21,000 years ago, ice-sheets covered North America and Eurasia, and sea-levels were much lower. This period, the peak of ice age conditions, is called the Last Glacial Maximum. 

 

Details

• By studying microscopic zooplankton called foraminifera, the team first found evidence from the past of an Indian Ocean El Niño.

• Foraminifera build a calcium carbonate shell, and studying these can tell us about the properties of the water in which they lived.

• The team measured multiple individual shells of foraminifera from ocean sediment cores and was able to reconstruct the sea surface temperature conditions of the past.

• This could be similar to the El Niño phenomenon of the Pacific Ocean bringing more frequent and devastating floods and drought to several densely-populated countries around the Indian Ocean region.

• If current warming trends continue, this new Indian Ocean El Niño could emerge as early as 2050. 

• The Indian Ocean has the capacity to harbor much larger climate variability than observed during the last few decades or a century. The Indian Ocean can arise under increased greenhouse gas forcing of global climate change.

• Under present-day conditions, changes in the Indian Ocean Dipole and the El Niño–Southern Oscillation strongly affect Indian Monsoon variability from year to year.

• If the hypothesized ‘equatorial mode’ emerges in the near future, it will pose another source of uncertainty in rainfall prediction and will likely amplify swings in monsoon rainfall.

• It could bring more frequent droughts to East Africa and southern India and increased rainfall over Indonesia.