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Over-projected Pacific warming and extreme El Niño frequency due to CMIP5 common biases
罗京佳
南京信息工程大学
Extreme El Niño events severely disrupt global climate, causing pronounced socio-economic losses. A prevailing view is that extreme El Niño events, defined by total precipitation or convection in Niño3 area, would increase twofold in future. However, this projected change was drawn without correcting potential impacts of CMIP5 models’ common biases. Here, we find that models’ systematic biases in simulating the tropical climate change over the past century can reduce the reliability of the projected change in the Pacific sea surface temperature (SST) and its-related extreme El Niño frequency. The projected Pacific SST change, after correcting impacts of 13 common biases, displays a La Niña-like rather than El Niño-like change. Consequently, the extreme El Niño frequency, which is highly linked to the zonal distribution of the Pacific SST change, would remain mostly unchanged under CMIP5 warming scenarios. This finding increases the confidence in coping with climate risks associated with global warming.