The North central Pacific (NCP) has experienced persistent and intensified surface warming, recording the fastest warming rate among the global oceans in the recent decade. The intensified warming unexpectedly persisted through the 2023-2024 strong El Niño. The cause for the persistent and accelerated NCP warming is unknown. During El Nino, an anomalously deepened Aleutian Low generally leads to cooler sea surface temperatures (SSTs) in the NCP, and vice-versa during La Nina. Here we show that under greenhouse warming, the ENSO impact undergoes an asymmetric change that contributes to an accelerated NCP warming.  Under greenhouse warming, teleconnection of El Nino features an eastward-shifted Pacific North America pattern, which weakens the effect of an anomalous NCP cooling, whereas the impact of the anomalous warming during La Nina intensifies. We show that the asymmetric response of ENSO impact drives more frequent prolonged marine heatwave event in the NCP. Thus, accelerated warming of the NCP as seen during 2017-2024 are likely to occur more often or to continue, with severe impacts on local marine ecosystems.

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