Study authors John Fasullo and Nan Rosenbloom,from the US-basedNational Center for Atmospheric Research,said analysis showed an interaction between the smoke pollution and increased cloud cover,which likely influenced the La Nina event of 2020-22.
The US researchers ran two sets of climate models - one that included the smoke pollution produced by the Black Summer bushfires and the other that did not. They found a significant difference between the two,which suggests the bushfire smoke that blew from Australia’s coastline increased cloud cover over the south-west Pacific and cooled the sea surface.
The smoke’s tiny particles attracted moisture to them,like theprocess used in cloud seeding,which then increased cloud cover and cooled the surface of the ocean.
“This may become more prevalent under climate change as wildfires are projected to intensify and become more frequent,” the researchers warned.
You’re probably familiar with the El Nino Southern Oscillation cycle over the Pacific Ocean,which affects weather worldwide. For most of Australia,El Nino brings dry weather,while La Nina brings wet weather. It’s one of the most important drivers of unusual weather over the entire globe.
The south-eastern Pacific is where the first signs of an El Nino or La Nina weather pattern form,and this new research suggests the warming ocean “flipped” the climatic conditions into the La Nina phase.