The El Nino-Southern Oscillation (ENSO) is the dominant mode of interannual climate variability on Earth, yet climate models do not yet provide a clear consensus on how ENSO will change in the future.

Paleoclimate reconstructions provide an opportunity to extend records of ENSO back through the last millennium to better characterise the full range of natural and unforced variability of this climate system, but different reconstructions often produce divergent results.

This study employs a new statistical approach to reconstructing ENSO which enables us to identify times in the past when palaeo-ENSO reconstructions are most robust.

We find that ENSO reconstructions we most reliable from 1580-1700, and from 1825 to present. At other times changes in teleconnections in the west Pacific/Australasia region appear to have been altered from their present day ENSO relationship.

This new statistical method and the findings that emerge from it have the potential to improve our understanding of the full range of ENSO variability, including impact patterns unlike those witnessed in the observational record.

  • Paper: Dätwyler, C, Abram, NJ, Grosjean, M, Wahl, ER, Neukom, R. El Niño–Southern Oscillation variability, teleconnection changes and responses to large volcanic eruptions since AD 1000. Int J Climatol. 2019; 39: 2711– 2724.
  • Picture (Above): Ocean sunset by Riccardo Maria Mantero.