资源环境科技发展态势分析平台

We explore the effect of Atlantic meridional overturning circulation (AMOC) slowdown on global marine heatwaves (MHWs) under anthropogenic warming by maintaining AMOC strength in climate model simulations throughout the twenty-first century. The AMOC slowdown has an insignificant effect on global MHWs during the past four decades, except those over the North Atlantic warming hole (NAWH) where the weakened AMOC reduces the occurrence and duration of MHWs by about half by creating a cooler mean-state sea surface temperature. As the AMOC continues weakening in current century, its effect becomes significant on MHWs in the North Atlantic and Pacific Oceans. The weakened AMOC induces a bipolar-seesaw like change in MHW frequencies, with more frequent MHWs in the Southern Hemisphere, but less frequent MHWs in the North Hemisphere except over the NAWH. The reason for the exception is that the NAWH region would enter a near-permanent MHW state without an AMOC slowdown.