El Niño Southern Oscillation (ENSO)

El Niño events in the Central Pacific may be changing due to climate change, but long records to support this are lacking. Here, the authors present sea surface temperature reconstructions from tree cellulose for the last 800 years which suggest the variability of Central Pacific El Niño events has increased.

The El Niño-Southern Oscillation is one of the largest sources of global climate variability, yet our understanding relative to the Topical Pacific mean state is poor. Here, geochemical analyses of marine plankton reveal a strong link between zonal sea-surface temperatures and ENSO variability.

Despite advances in ENSO modeling, super El Niño events remain largely unpredictable. Hameed et al. postulate that ENSO-IOD interaction is crucial for super El Niño development and identify a self-limiting factor that constrains ENSO dynamics from generating these extreme events on their own.

Sea surface temperature anomalies in the tropical Pacific can influence global atmospheric circulation, yet prediction of this atmospheric signal is limited to less than 1 year. Here, the authors present observational and modelling evidence for multi-year predictability.

Biennial variability has intensified in the Pacific in recent decades, but the cause of this increase is not fully understood. Here, with statistical analyses and numerical experiments, the authors show that an Atlantic capacitor effect has given rise to this enhanced biennial variability since the early 1990s.

El Niño tends to follow 2 years after volcanic eruptions, but the physical mechanism behind this phenomenon is unclear. Here the authors use model simulations to show that a Pinatubo-like eruption cools tropical Africa and drives westerly wind anomalies in the Pacific favouring an El Niño response.

The role of thermocline mixing in the Pacific cold tongue in the propagation of ENSO remains uncertain. Here, Liu et al. show a persistent occurrence of mixing events in the middle and lower parts of the thermocline, particularly during tropical instability waves and under La Niña conditions.

Evolution of the El Niño-Southern Oscillation through the Holocene remains uncertain. Here, via fully coupled model simulations, the authors show that increased Saharan vegetation and reduced dust emissions 6 kyr BP significantly affect ENSO variability through changes in the West African Monsoon strength.

Chronological assumptions in marine sediment records can result in uncertainties in paleoenvironmental reconstructions. Here, using computed tomography to identify in situ woody debris, the authors construct a robust ¹⁴C chronology and reassess ventilation ages in the Eastern Equatorial Pacific during the LGM.

The phase of the Interdecadal Pacific Oscillation (IPO) impacts global temperatures. Here, the authors show that a build-up of off-equatorial western tropical Pacific heat content allows ENSO events to trigger IPO phase changes, with a predicted switch to a positive IPO for 2015–2019 and larger warming trends.

The western tropical Pacific is a main source of heat and moisture for the global atmosphere, yet the mechanism for the multidecadal sea surface temperature variability in this region remains unknown. Here, the authors show that this variability is forced by the remote Atlantic multidecadal oscillation

El Niño Southern Oscillation affects seasonal climate worldwide; however, it is uncertain how it impacts global crop yields. Here, the authors present a global assessment of the impacts of El Niño Southern Oscillation on crop productivity and show large differences among regions, crop types and cropping technologies.

Identifying the effects of global warming on regional water cycle extremes, such as the ongoing drought in California, remains a challenge. Here, the authors present the results of multi-model simulations that project an increase in drought and flooding towards the end of the century.

El Niño and La Niña (ENSO) events influence global river flow and are often used as an early indicator of potential flooding. Here, the authors show that the probability of ENSO-driven flood hazard is more complex than is often perceived, and highlight the importance of considering hydrological response.

Record temperatures in mainland Southeast Asia in April 2016 had severe impacts on the population. Thirumalaiet al. show that all April extremes occur after El Niño years, and that global warming has increased the likelihood of such extremes.

Over 5,000 km of open ocean separate central and eastern Pacific coral reefs. Here, the authors combine a biophysical dispersal model with genetic data to show that eastern Pacific coral populations have been isolated from western sources of larval recruitment since the 1997-98 El Niño-induced bleaching event.

Sporadic surface melt over the West Antarctic Ice Sheet is not fully understood. Here, the authors report on an extensive melting episode in the Ross Ice Shelf area in 2016 and use comprehensivein situobservations and model simulations to highlight the role of the strong El Niño event.

Climate oscillations such as El Niño Southern Oscillation may impact global crop production. Here, the authors, using a unified framework of multiple climate oscillations, find that from 1961 to 2010 over two-thirds of the global cropland is located where crop productivity is influenced by climate oscillations.

California lies in the transition zone where mid-latitude regions are expected to become wetter and subtropical regions drier, and precipitation projections for the region remain uncertain. Here the authors use a multitude of models to show consistent increases in California precipitation under a business-as-usual scenario.

El Niño events have important impacts on tropical cyclone activity over the western North Pacific. Here, the authors show that short duration El Niño could significantly shift the tropical cyclone rapid intensification westward by transporting ocean heat energy to the western Pacific.

Teleconnections between different flavours of El Niño and Arctic climate change are inherently uncertain in the context of warming. Here, the authors show that Central Pacific El Niño contributes to summer Arctic cooling and sea-ice increase via an Equator-Arctic teleconnection on interannual timescales.

El Niño Southern Oscillation has a strong impact on current strength and ocean temperatures off the western Australian coast, but long-term variability is poorly understood. Zinke et al.show a strong link between La Niña and El Niño events and decadal Leeuwin current variability in coral records since 1795.

ENSO end members El Niño and La Niña are linked to elevated coastal hazards across the Pacific region. Here, the authors show that the wave conditions and coastal response for the 2015–16 El Niño indicate that it was one of the most significant events of the last 145 years.

The terrestrial carbon cycle is strongly influenced by El Niño/Southern Oscillation (ENSO), but how this relationship will change in future is not clear. Here the authors use state-of-the-art models to show that the sensitivity of the carbon cycle to ENSO will increase under future climate change.

Ocean acidification due to the industrial era is a major marine environmental concern, yet little is known on the historical ocean pH changes prior to human influence. Here, Wu et al. show that tropical South Pacific seawater pH is linked to ENSO pacing and has recently been decreasing rapidly.

It has been suggested that tree phenology may be regulated by climatic oscillations. Here, Detto et al. present a 30 year tropical forest dataset that suggests leaf and fruit production is coordinated with ENSO cycles, with greater leaf fall observed prior to El Niño followed by greater seed production.