Climate change affects El Nino, UH-led research finds

A warming planet will bring more frequent and stronger El Nino events, which in turn could lead to severe weather and social upheaval, a University of Hawaii research team has concluded.

El Nino is normally associated with warmer sea-surface temperatures in the tropical Pacific, and typically shifts weather patterns around the globe.

A team of climate researchers led by Bin Wang of the UH International Pacific Research Center examined 33 El Nino events from 1901 to 2017, and found that all the events prior to 1970 originated in the eastern Pacific, while all events afterward started in the western-central Pacific. Four out of the five extreme El Nino events they examined took place after 1970.

Wang and the team focused on what was causing the changes in El Nino behavior, including increased sea surface temperatures and wind patterns. They observed the location where El Nino warming began, its evolution and its ultimate strength.

“Simulations with global climate models suggest that if the observed background changes continue under future anthropogenic (human-caused) forcing, more frequent extreme El Nino events will induce profound socioeconomic consequences,” Wang reported.

The results appear in the journal Proceedings of the National Academy of Sciences.

Strong El Nino events have led to droughts — which in turn leads to forest fires and famine — in the Pacific islands and Australia but increased flooding by heavy rainfall in the northern coasts of South America.

Warm temperatures have adverse affects on fisheries and coral reefs around the globe.

Hawaii has felt many of these effects and others, such as severe hurricane activity and changes in sea level.

Wang and his team found that the frequency of extreme El Nino events will be on the rise as global warming continues. A classification system in their study is an important tool in modeling El Nino and La Nina events.

They are continuing to explore how the work that has been done can be used to better predict future El Nino events.

Currently, neutral conditions persist after an El Nino earlier this year.