“…Due to geographically heterogeneous trends (e.g., McPhaden et al., 2020), different long‐term trends are observed in the tropical oceans, including in the ENSO (e.g., Fedorov & Philander, 2000; Hu et al., 2020; L’Heureux, et al., 2013; Lee et al., 2022; Zheng et al., 2016; Zhang et al., 1998) and Atlantic Niño (Li, Tan, et al., 2023) regions. Such trends affect the strength estimates of ENSO (e.g., Li et al., 2019) and Atlantic Niño (Li, Tan, et al., 2023). Physically, both ENSO and Atlantic Niño are seasonal‐to‐interannual time‐scale phenomena, and so it is a challenge to monitor their seasonal‐to‐interannual variations in the presence of differential background warming.…”