More According to new research, multiyear La Nina events will occur because to global warming

According to recent study published in the journal Nature, more multiyear La Nina occurrences are anticipated under sustained global warming. La Nina periods that last for two or more years straight are known to have cumulative effects that last for a long time, such as increased wildfires, floods, and changed hurricane, cyclone, and monsoon patterns.

After a warm El Nino event, which typically lasts a year, the cool La Nina phase tends to emerge. The El Nino-Southern Oscillation (ENSO), which affects ocean surface temperatures and disrupts tropical wind and rainfall patterns, has two alternating phases. It is the planet’s most significant annual climatic variation.

According to studies from China, Australia, and the US during a 100-year period, the frequency of multiyear La Nina occurrences is anticipated to significantly rise, rising from 19% in a scenario with low greenhouse gas emissions to 33% in a scenario with high emissions. In the current climate, a severe El Nino in the northern winter reduces temperatures in the subtropical North Pacific, resulting in a La Nina in the following winter with southern wide-ranging sea surface temperature and easterly wind anomalies. The sluggish heat recharging of the upper ocean caused by these southern trends creates the perfect environment for La Nina to continue into its second year.

The equatorial eastern Pacific warms more quickly under global warming, intensifying the easterly wind anomalies, which then stretch further north and slow down the equatorial Pacific’s heat recharge. As a result, the upper ocean becomes cooler, which makes it more simpler for the first-year La Nina’s decaying effects to be sustained by the low sea surface temperatures.

Thus, a multiyear La Nina is much more effectively triggered by an overall warming of the Pacific, which allows for more effective tropical-subtropical interactions, according to the researchers. The study’s lead author, Geng Tao of Ocean University of China, noted that the results “indicate that weather extremes as seen during the 2020–2022 La Nina will probably occur more frequently in the near future.”

The findings of this research support recommendations to lower greenhouse gas emissions in order to lessen the negative effects of an intensifying multiyear La Nina, according to Jia Fan, a co-corresponding author from the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS).