Anthropogenic and natural influences on record 2016 marine heat waves

In 2016 a quarter of the ocean surfaceexperienced either the longest or most intense marineheatwave (Hobday et al. 2016) since satellite recordsbegan in 1982. Here we investigate two regions—Northern Australia (NA) and the Bering Sea/Gulf ofAlaska (BSGA)—which, in 2016, experienced theirmost intense marine heat waves (MHWs) in the 35-year record. The NA event triggered mass bleachingof corals in the Great Barrier Reef (Hughes et al.2017) while the BSGA event likely fed back on theatmosphere leading to modified rainfall and temperaturepatterns over North America, and it is feared itmay lead to widespread species range shifts as wasobserved during the “Blob” marine heat wave whichoccurred immediately to the south over 2013–15(Belles 2016; Cavole et al. 2016). Moreover, from aclimate perspective it is interesting to take examplesfrom climate zones with very different oceanographiccharacteristics (high-latitude and tropics). We demonstratethat these events were several times morelikely due to human influences on the climate