Solar Forcing of ENSO on Century Timescales

• Published in: Geophysical Research Letters
• Main Authors: Paul S. Wilcox, Manfred Mudelsee, Christoph Spötl, R. Lawrence Edwards
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2023
• Subjects: ENSO; North Pacific; speleothems; anthropocene; Geophysics. Cosmic physics; QC801-809; Pacific; aleutian low; Alaska
• Online Access: https://doi.org/10.1029/2023GL105201; https://doaj.org/article/d23b71aa6c9a4db9a0d4e763a9f2f4b0

Abstract Understanding how El Niño‐Southern Oscillation (ENSO) responds to natural variability is of key importance for future climate projections under a warming climate. However, there is no clear consensus on what drives ENSO's variability on centennial timescales. Here, we find that the epikarst in southeastern Alaska is effective at filtering ENSO and solar irradiance signals from the Aleutian Low regional climate, which are subsequently recorded in speleothem proxy data. By applying a correlation test, we find that ENSO was significantly influenced by solar irradiance over the past ∼3,500 years. This relationship dissolved after ∼1970 CE, with ENSO now being dominated by anthropogenic forcing. This implies a new ENSO mean state that will need to be incorporated into future climate projections.