Reduced Distinctiveness of Extreme El Niño Teleconnections in Warmer Climates

Abstract In today's climate, extreme El Niño events (e.g., 1982–1983, 1997–1998) generate stronger and eastward‐shifted teleconnections relative to moderate El Niño and La Niña events, leading to distinct North American impacts such as enhanced rainfall over California and warming over northeastern North America. A multi‐model, multi‐member, multi‐scenario CMIP6 analysis shows that as warming exceeds +2°C, extreme El Niño teleconnections shift even farther eastward (by 20°), weaken (by 33% at +3.5°C over North America) and develop a negative North Atlantic Oscillation–like response, echoing the changes seen in moderate El Niño–Southern Oscillation (ENSO) phases. Extreme El Niño North American impacts become progressively closer to those of moderate events, with little distinctiveness left beyond +3.5°C. Although future teleconnection changes are much stronger for extreme El Niños, their increased frequency and altered future patterns contribute only modestly to the overall change in ENSO teleconnections.