Understanding the tropical Pacific response to global warming remains challenging. Here we use a range of Coupled Model Intercomparison Project Phase 6 greenhouse warming experiments to assess the recent and future evolution of the equatorial Pacific east–west temperature gradient and corresponding Walker circulation. In abrupt CO₂-increase scenarios, many models generate an initial strengthening of this gradient resembling an ocean thermostat, followed by a small weakening; other models generate an immediate weakening that becomes progressively stronger, establishing a pronounced eastern equatorial Pacific warming pattern. The initial response in these experiments is a strong predictor for the intensity of this pattern simulated in both abrupt and realistic warming scenarios, but not in historical simulations showing no multi-model-mean warming trend in this region. The likely explanation is that the recent CO₂-driven changes in the tropical Pacific are masked by aerosol effects and a potential ocean-thermostat-related delay, while the eastern equatorial Pacific warming pattern will emerge as greenhouse gases overcome aerosol forcing.

了解热带太平洋对全球变暖的反应仍然具有挑战性。在这里，我们使用一系列耦合模型比对项目第 6 阶段温室变暖实验来评估赤道太平洋东西温度梯度和相应的沃克环流的近期和未来演变。在突然的 CO ₂- 增加情景，许多模型会产生类似于海洋恒温器的这种梯度的初始加强，然后是小幅减弱；其他模型产生的立即减弱会逐渐增强，从而建立明显的赤道太平洋东部变暖模式。这些实验中的初始响应是在突然和现实变暖情景中模拟的这种模式强度的一个强有力的预测指标，但在历史模拟中没有显示该地区没有多模式平均变暖趋势。可能的解释是，最近由 CO ₂驱动的热带太平洋变化被气溶胶效应和潜在的海洋恒温器相关延迟所掩盖，而随着温室气体克服气溶胶强迫，东赤道太平洋变暖模式将出现。