Climate change could revive an El Nino-like weather system in the Indian Ocean that has lain dormant for millennia, according to new research published in Science Advances. The study found that small changes in sea surface temperatures over the ocean could result in weather patterns similar to the El Ninos that occur over the Pacific Ocean, which can cause both flooding and droughts. The research found that increasing or decreasing average global temperatures by just a few degrees could result in the Indian Ocean having its own El Nino within the next 30 years.
Climate change is likely to cause significant impacts for the countries around the Indian Ocean rim. Eastern Africa is likely to see notable temperature rises, increased variation in rainfall patterns and increased frequency of drought; typhoons, cyclones and floods are projected to become more intense in Southeast Asia and India; and Western Australia is facing rising temperatures and considerably less rainfall.
This new study shows rising temperatures in the Indian Ocean could trigger it to behave in a similar manner to the El Nino ocean-atmospheric phenomenon in the Pacific Ocean – an oscillation within which warm waters, normally pushed west by trade winds, collect in central and eastern areas of the Pacific around every seven years. This phenomenon affects surrounding Pacific coastlines, but also has an influence on weather events worldwide via “teleconnections”. One example is the current “megadrought” in the western US, which is being exacerbated by the phenomenon.
The research indicates the Indian Ocean previously operated in this fluctuating state in the last Ice Age, and a re-emergence, which could occur by 2050, could see an increase in storms, droughts and floods in surrounding countries, while having a significant impact on water availability.
Separate research on the Indian Ocean Dipole, a similar phenomenon relating to the difference in temperature between the western and eastern Indian Ocean, indicates hot and dry conditions in eastern Australia, which fuelled this year’s bushfires, could also become more frequent in the future.
These studies highlight the uncertainty of the exact nature of future climatic changes, with rising global average temperatures already strengthening existing El Nino events – and their repercussions.