Persistently active El Niño-Southern Oscillation since the Mesozoic.

The El Niño-Southern Oscillation (ENSO), originating in the central and eastern equatorial Pacific, is a defining mode of interannual climate variability with profound impact on global climate and ecosystems. However, an understanding of how the ENSO might have evolved over geological timescales is still lacking, despite a well-accepted recognition that such an understanding has direct implications for constraining human-induced future ENSO changes. Here, using climate simulations, we show that ENSO has been a leading mode of tropical sea surface temperature (SST) variability in the past 250 My but with substantial variations in amplitude across geological periods.

Central-Pacific El Niño-Southern Oscillation less predictable under greenhouse warming.

El Niño-Southern Oscillation (ENSO) is the dominant mode of interannual climate variability in the tropical Pacific, whose nature nevertheless may change significantly in a warming climate. Here, we show that the predictability of ENSO may decrease in the future. Across the models in the Coupled Model Intercomparison Project Phase 6 (CMIP6), we find a robust decrease of the persistence and predictability for the Central Pacific (CP) ENSO under global warming, notably in passing through the boreal spring.

Deglacial variability of South China hydroclimate heavily contributed by autumn rainfall.

The deglacial hydroclimate in South China remains a long-standing topic of debate due to the lack of reliable moisture proxies and inconsistent model simulations. A recent hydroclimate proxy suggests that South China became wet in cold stadials during the last deglaciation, with the intensification proposed to be contributed mostly by the East Asian summer monsoon (EASM). Here, based on a deglacial simulation in a state-of-the-art climate model that well reproduces the evolution of EASM, winter monsoon (EAWM) and the associated water isotopes in East Asia, we propose that the intensified hydroclimate in South China is also contributed heavily by the rainfall in autumn, during the transition between EASM and EAWM.