Over-projected Pacific warming and extreme El Niño frequency due to CMIP5 common biases |
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| Authors: | Tao Tang Jing-Jia Luo Ke Peng Li Qi Shaolei Tang |
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| Institution: | Institute for Climate and Application Research (ICAR), Nanjing University of Information Science and Technology, Nanjing 210044, China;Key Laboratory of Meteorological Disaster of Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044, China |
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| Abstract: | Extreme El Niño events severely disrupt the global climate, causing pronounced socio-economic losses. A prevailing view is that extreme El Niño events, defined by total precipitation or convection in the Niño3 area, will increase 2-fold in the future. However, this projected change was drawn without removing the potential impacts of Coupled Model Intercomparison Project phase 5 (CMIP5) models’ common biases. Here, we find that the models’ systematic biases in simulating 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 removing the 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 confidence in coping with climate risks associated with global warming. |
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| Keywords: | common model biases Pacific SST change projection extreme El Niñ o frequency change global warming emergent constraint method |
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