Marine heatwaves (MHWs)—periods of extremely high ocean temperatures in specific regions—have occurred in all of Earth’s ocean basins over the past two decades, with severe negative impacts on marine organisms and ecosystems. However, for most individual MHWs, it is unclear to what extent they have been altered by human-induced climate change. We show that the occurrence probabilities of the duration, intensity, and cumulative intensity of most documented, large, and impactful MHWs have increased more than 20-fold as a result of anthropogenic climate change. MHWs that occurred only once every hundreds to thousands of years in the preindustrial climate are projected to become decadal to centennial events under 1.5°C warming conditions and annual to decadal events under 3°C warming conditions. Thus, ambitious climate targets are indispensable to reduce the risks of substantial MHW impacts.

海洋热浪（MHW）——特定地区海洋温度极高的时期——在过去的二十年中发生在地球的所有海洋盆地，对海洋生物和生态系统造成严重的负面影响。然而，对于大多数个人 MHW，尚不清楚它们在多大程度上被人为气候变化所改变。我们表明，由于人为气候变化，大多数有记录的、大型和有影响的 MHW 的持续时间、强度和累积强度的发生概率增加了 20 倍以上。在前工业化气候中每几百到几千年才发生一次的 MHW 预计将在 1.5°C 变暖条件下成为十年至百年事件，在 3°C 变暖条件下成为每年至十年事件。因此，