Will global warming intensify extreme weather swings?
FRISCO — Global warming could increase the frequency of extreme La Niña events in the Pacific Ocean, with more droughts in southwestern United States, floods in the western Pacific regions and increased Atlantic hurricane activity.
The international study, published in Nature Climate Change, used advanced modeling to show how increased land-area heating, combined with more frequent El Niños, will feed a cycle of extreme La Niñas.
In a press release, the scientists explained that most extreme La Niñas happen in the year immediately after an extreme El Niño, so some parts of the world could experience weather patterns that switch between extremes of wet and dry.
El Niño and La Niña events are opposite phases of the natural climate phenomenon, the El Niño/Southern Oscillation. Extreme La Niña events occur when cold sea surface temperatures in the central Pacific Ocean contrast with the warming land areas of Maritime Southeast Asia in the west and create a strong temperature gradient.
“Our previous research showed a doubling in frequency of extreme El Niño events, and this new study shows a similar fate for the cold phase of the cycle. It shows again how we are just beginning to understand the consequences of global warming,” said co-author Mat Collins, with Exeter’s College of Engineering, Mathematics and Physical Sciences.
The new research was led by scientist Dr Wenju Cai, from the Commonwealth Scientific and Industrial Research Organisation and included scientists from Australia, China, the US, France and Peru.
Dr. Cai indicated the potential impact of this change in climate.
“An increased frequency in extreme La Niña events, most of which occur in the year after an extreme El Niño, would mean an increase in the occurrence of devastating weather events with profound socio-economic consequences,” Cai said.