Changing El Niño–Southern Oscillation in a warming climate

Abstract

Originating in the equatorial Pacific, the El Niño-Southern Oscillation (ENSO) has highly consequential global impacts, motivating the need to understand its responses to anthropogenic warming. In this Review, we synthesize advances in observed and projected changes of multiple aspects of ENSO, including the processes behind such changes. As in previous syntheses, there is an inter-model consensus of an increase in future ENSO rainfall variability. Now, however, it is apparent that models that best capture key ENSO dynamics also tend to project an increase in future ENSO sea surface temperature variability and, thereby, ENSO magnitude under greenhouse warming, as well as an eastward shift and intensification of ENSO-related atmospheric teleconnections -the Pacific-North American and Pacific-South American patterns. Such projected changes are consistent with palaeoclimate evidence of stronger ENSO variability since the 1950s compared with past centuries. The increase in ENSO variability, though underpinned by increased equatorial Pacific upper-ocean stratification, is strongly influenced by internal variability, raising issues about its quantifiability and detectability. Yet, ongoing coordinated community efforts and computational advances are enabling long-simulation, large-ensemble experiments and high-resolution modelling, offering encouraging prospects for alleviating model biases, incorporating fundamental dynamical processes and reducing uncertainties in projections.

Modulation of the ENSO teleconnection to the North Atlantic by the tropical North Atlantic and Caribbean

“…As a result, one would expect any influences from the TNA SSTA to be reduced during extreme events. This interaction may also increase in importance in the future if climate change influences the strength of ENSO events (Cai et al, 2021). As this study only considers El Niño events, future studies should determine if the negative TNA SSTAs that result from a La Niña interact similarly with the Walker gradient.…”

Causal influences of El Niño–Southern Oscillation on global dust activities

“…As high-resolution models may improve the simulations of dust emission processes (Knippertz and Todd, 2012) and their connection with ENSO, further studies might use outputs from high-resolution models. Because there is a strong link between dust deposition over ocean and ocean biogeochemistry and carbon cycle (Rap et al, 2018) and there are possible changes in ENSO properties under a warming environment (Cai et al, 2021;Timmermann et al, 2018;, further works related to ENSO impacts on oceanic carbon cycle are necessary. While there is uncertainty in the projections of global dust deposition (Carslaw et al, 2010) and there is low confidence in projecting dust activities under greenhouse warming (Thornhill et al, 2020), additional studies may focus on the future impacts of ENSO on dust activities.…”

“…Dust emission, transport, and deposition are driven by vegetation cover, soil moisture, precipitation, and wind speed (Carslaw et al, 2010;Kanakidou et al, 2018;Kok et al, 2021;Pi et al, 2019;Thornhill et al, 2020). Hence, ENSO impacts on these variables (Cai et al, 2021;Le and Bae, 2020; are likely to result in ENSO-induced changes in dust activities. For instance, ENSO is shown to have influences on dust activities over Australia (Marx et al, 2009), the Sahara and Amazon basin (Boy and Wilcke, 2008), the regions from the Arabian Peninsula to Central Asia (Huang et al, 2021), South America (Shao et al, 2013), and East Asia (Jeong et al, 2018).…”

Reliability and Resiliency in South Asia's Power Sector - Pathways for Research, Modeling, and Implementation

“…Failure of monsoon rainfalls (also known as droughts) severely impact the continuous electricity supply and reliability of the grid (Repair 2019). The El Niño-Southern Oscillation and IOD teleconnections to the monsoons have been identified (De Silva M. and Hornberger 2019), and these atmospheric teleconnections are predicted to be severe with climate change (Cai et al 2021). Studies show that there is a significant probability of a failing northeastern monsoon for the El Niño phase and higher precipitation for the La Niña phase.…”