Teleconnections of El Niño Southern Oscillation in Climate Variability

The El Niño–Southern Oscillation (ENSO) constitutes the foremost source of interannual variability in the global climate system, driven by sea-surface temperature anomalies in the equatorial Pacific. Through atmospheric and oceanic teleconnections, ENSO events modulate large-scale circulation patterns far beyond the tropics, influencing temperature, precipitation and storm tracks across multiple continents. Key extratropical manifestations include shifts in the Pacific–North American (PNA) pattern, alterations of the North Atlantic Oscillation (NAO) phase, and modulation of monsoon systems. These teleconnections propagate via tropospheric Rossby waves and, in some regions, via vertical coupling with the stratosphere. The spatial character and strength of ENSO teleconnections are non-stationary, varying with event flavour (eastern vs central Pacific), event magnitude (moderate vs extreme) and background state of the mean flow. Understanding these global linkages underpins improvements in seasonal forecasting, risk assessment for droughts and floods, and adaptation strategies for agriculture, water management and public health.

Research from Nature Portfolio

Recent studies have identified a distinct teleconnection pattern associated specifically with extreme El Niño events. When sea-surface temperature anomalies exceed a deep convection threshold in the eastern Pacific, the canonical Pacific–North American response shifts eastward, yielding enhanced wet anomalies over the western United States and pronounced warming over Canada and the northern United States. This reproducible pattern shows greater consistency across events than moderate El Niño or La Niña cases, offering improved predictability for North American seasonal climate. In parallel, a comprehensive analysis of ENSO’s full lifecycle using satellite, in situ and reanalysis data has revealed a far broader footprint of impacts than previously recognised. Neutral phases of ENSO are shown to coincide with significant anomalies of sea surface temperature, land surface air temperature and precipitation across all continents, underscoring the importance of monitoring the entire ENSO evolution rather than focusing solely on peak phases.

Teleconnections of El Niño Southern Oscillation in Climate Variability publication trend

The graph below shows the total number of articles in teleconnections of el niño southern oscillation in climate variability across all publications each year (not limited to Nature Index journals).

Technical terms

El Niño–Southern Oscillation (ENSO): A coupled ocean–atmosphere phenomenon in the tropical Pacific marked by warm (El Niño) and cold (La Niña) phases, driving global climate variability.

Teleconnection: A large-scale linkage between climate anomalies in widely separated regions, often mediated by atmospheric wave trains or ocean currents.

Pacific–North American (PNA) pattern: A principal mode of atmospheric variability linking tropical Pacific anomalies to pressure and temperature variations over North America.

North Atlantic Oscillation (NAO): A fluctuation in the pressure gradient between the Azores High and Icelandic Low, affecting weather over Europe and eastern North America.

Indian Ocean Dipole (IOD): A zonal gradient of sea-surface temperature anomalies in the Indian Ocean that influences regional monsoons and can be modulated by ENSO.

Tropospheric pathway: The direct propagation of climate signals through the lower atmosphere, primarily via Rossby wave trains.

Stratospheric pathway: A secondary route for teleconnections involving perturbations to the stratospheric polar vortex and downward coupling to the surface circulation.

References

1. Predictability of Indian Ocean precipitation and its North Atlantic teleconnections during early winter. npj Climate and Atmospheric Science (2023).
2. A distinct and reproducible teleconnection pattern over North America during extreme El Niño events. Scientific Reports (2024).
3. Subseasonal Variation in the Winter ENSO-NAO Relationship and the Modulation of Tropical North Atlantic SST Variability. Climate (2023).
4. Separating the stratospheric and tropospheric pathways of El Niño–Southern Oscillation teleconnections. Environmental Research Letters (2014).
5. A New Picture of the Global Impacts of El Nino-Southern Oscillation. Scientific Reports (2019).