a–d, For each region, displacements from select locations (diamonds) are shown for all months with an active MHW from 1982 to 2019 (open circles). Displacements and years of the most intense MHWs are also shown for each location (filled circles). Spatial scales differ between panels; for reference, displacement distances for labelled events are: in a, 1,039 km (Gulf of Alaska, 2014), 895 km and 807 km (US West Coast, 2005 and 2014, respectively); in b, 418 km and 161 km (Northwest Atlantic, 2012 and 2016, respectively); in c, 362 km (Western Australia, 2011), 526 km (Northern Australia 2016) and 251 km (Tasman Sea 2016), and in d, 2,354 km (Eastern Tropical Pacific, 2015), 2,135 km and 1,926 km (South American West Coast, 1997 and 2016, respectively). In contrast to Fig. 3, MHWs here were calculated without detrending SST anomalies relative to the 1982–2011 climatology. Background colour indicates 1982–2019 mean SST.