Warming climate will bring more extreme ' El Nino ' eventsRising global temperatures are likely to double the frequency of the most severe El Niños - the periodic atmospheric disruptions which affect weather across the globe . Tim Radford reports An El Niño is part of a natural cycle : a huge blister of heat in the equatorial Pacific , usually around Christmas - time . The phenomenon periodically triggers unseasonal floods in the western US , and extreme heat and forest fires in the Indonesian rainforest and the Australian bush . It happens and seems to have happened through human history . It has nothing to do with global warming or climate change . Except this : according to the latest study by climate scientists in Australia , the US , China and Britain , global warming is likely to make the most extreme El Niño events happen twice as frequently . Severely disrupted global weather patternsAn El Niño episode is characterised by - the scientists say in Nature Climate Change - " severely disrupted global weather patterns , affecting ecosystems , agriculture , tropical cyclones , drought , bushfires , floods and other extreme weather events worldwide . " So this is unlikely to be welcome news . Right now , and for the past year , conditions in the equatorial Pacific have been neither unusually warm nor unusually cool . There is no El Niño right now . But for two summers running , even without help from unusual Pacific conditions , Australia has been hit by record temperatures and appalling forest fires , so the news is ominous . Wenju Cai of Australia ' s CSIRO marine and atmosphere research and colleagues report in the journal that extreme El Niño events tend to happen when sea surface temperatures higher than 28 ° C develop in the normally cool and dry eastern Pacific . This can trigger big shifts in the atmospheric convection zones - areas of instability caused by temperature differences . These episodes have normally occurred every 20 years or so . Profound impactNow , as carbon dioxide levels rise and the global average temperatures creep up , these extreme events are likely to be twice as frequent : every decade or so . The last extreme event , in 1997 - 98 , caused an estimated $ 35 billion in damage and claimed an estimated 23 , 000 lives worldwide . It also made 1998 the hottest year ever in average global temperatures , a record that lasted for more than a decade . Mike McPhaden of the US National Oceanic and Atmospheric Administration , one of the paper ' s co - authors , said : " The question of how global warming will change the frequency of extreme El Niño events has challenged scientists for more than 20 years . This research is the first comprehensive examination of the issue to produce robust and convincing results . " The authors warn that potential future changes in such extreme events could have " profound socio - economic consequences . " They conclude : " With a projected large increase in extreme El Niño occurrences , we should expect more occurrences of devastating weather events , which will have pronounced implications for 21 st century climate . " 출처 : http : / / www . theecologist . org / News / news _ round _ up / 2246386 / warming _ climate _ will _ bring _ more _ extreme _ el _ nino _ events . html