The severe 2020 coral bleaching event in the tropical Atlantic linked to marine heatwaves

Marine heatwaves can amplify the vulnerabilities of regional marine ecosystems and jeopardise local economies and food resources. Here, we show that marine heatwaves in the tropical Atlantic have increased in frequency, intensity, duration, and spatial extent. Marine heatwaves are 5.1 times more frequent and 4.7 times more intense since the records started in 1982, with the 10 most extreme summers/falls in terms of marine heatwave cumulative intensity and spatial extension occurring in the last two decades. The extreme warming during the summer/fall of 2020 led to the largest bleaching event recorded along the Brazilian coast, with 85% of stony corals and 70% of zoanthids areas bleached in Rio do Fogo. The increase in the severity of the marine heatwaves in the western tropical Atlantic is not accompanied by trends in the strength of the local drivers. This suggests that weaker forcing can lead to more devastating marine heatwaves as the global ocean temperature rises due to climate change. Marine heatwaves in the tropical Atlantic have increased in frequency and intensity since records began and led to the largest coral bleaching event recorded on the Brazilian coast, according to analysis of sea surface temperature data combined with coral bleaching data.