Deep ocean warming-induced El Niño changes

The deep ocean, a vast thermal reservoir, absorbs excess heat under greenhouse warming, which ultimately regulates the Earth's surface climate. Even if CO2 emissions are successfully reduced, the stored heat will gradually be released, resulting in a particular pattern of ocean warming. Here, we show that deep ocean warming will lead to El Ni & ntilde;o-like ocean warming and resultant increased precipitation in the tropical eastern Pacific with southward shift of the intertropical convergence zone. Consequently, the El Ni & ntilde;o-Southern Oscillation shifts eastward, intensifying Eastern Pacific El Ni & ntilde;o events. In particular, the deep ocean warming could increase convective extreme El Ni & ntilde;o events by 40 to 80% relative to the current climate. Our findings suggest that anthropogenic greenhouse warming will have a prolonged impact on El Ni & ntilde;o variability through delayed deep ocean warming, even if CO2 stabilization is achieved. This paper shows that anthropogenic greenhouse warming will have a prolonged impact on El Ni & ntilde;o variability through delayed deep ocean warming, even if CO2 stabilization is achieved.