During the past 40 years El Nino is significantly linked to the negative polarity of the Southern Annular Mode (low SAM) during austral spring and summer, potentially providing long-lead predictability of the SAM and its associated surface climate conditions. In this study, we explore how this linkage may change if the tropical oceans continue their current trends since 1960. These observed warming trends are plausibly a forced response to increasing greenhouse gases and so can be used as a surrogate as to what might happen in the future. We generated forecasts for three recent extreme El Nino events initialised with the current ocean mean state and with the initial ocean mean state updated to include double the recent ocean temperature trends. We show that the strength of the extreme El Nino events is reduced on the warmer ocean mean state as a result of reduced thermocline feedback and weakened rainfall-wind-sea surface temperature coupling over the tropical eastern Pacific. The El Nino-low SAM relationship also weakens, implying reduced long-lead predictability of the SAM and associated surface climate impacts if the ocean temperature trends that have been observed over the past 60 years continue into the future.