Severe and widespread coral reef damage during the 2014-2017 Global Coral Bleaching Event
C. Mark Eakin, Scott F. Heron, Sean R. Connolly, Denise Devotta, Gang Liu, Erick Geiger, Jacqueline L. De La Cour, Andrea M. Gomez, William Skirving, Andrew H. Baird, Neal E. Cantin, Courtney S. Couch, Simon D. Donner, James Gilmour, Manuel González‐Rivero, Mishal Gudka, Hugo B. Harrison, Gregor Hodgson, Ove Hoegh-Guldberg, Andrew S. Hoey, Mia O. Hoogenboom, Terry P. Hughes, Meaghan E. Johnson, James T. Kerry, Tadashi Kimura, Jennifer Mihaly, Aarón Israel Muñiz-Castillo, David Obura, Morgan S. Pratchett, Andrea Rivera-Sosa, Claire L. Ross, Jennifer Stein, Angus Thompson, Gergely Torda, T. Shay Viehman, Cory Walter, Shaun Wilson, Benjamin L. Marsh, Blake L. Spady, Noel Dyer, Thomas C. Adam, Pedro M. Alcolado, Mahsa Alidoostsalimi, Parisa Alidoostsalimi, Lorenzo Alvarez-Filip, Mariana Álvarez‐Noriega, Jesús Ernesto Arias‐González, Keisha D. Bahr, Peter Barnes, José Enrique Barraza, Julia K. Baum, Andrew G. Bauman, Maria Beger, Kathryn Berry, Pia Bessell‐Browne, Bigot Lionel, Victor Bonito, Ole Brodnicke, David Burdick, Deron E. Burkepile, April Burt, John A. Burt, Ian R. Butler, Jamie M. Caldwell, Yannick Chancerelle, Chaolun Allen Chen, Kah-Leng Cherh, Michael J. Childress, Darren J. Coker, Bryan Costa, Georgia Coward, M. James C. Crabbe, Thomas Dallison, Steven J. Dalton, Thomas M. DeCarlo, Crawford Drury, Ian Drysdale, Clinton B. Edwards, Linda Eggertsen, Eylem Elma, Rosmin S. Ennis, Richard D. Evans, Gal Eyal, Douglas Fenner, Baruch Figueroa-Zavala, Jay Fisch, Michael D. Fox, Elena Gadoutsis, Antoine Gilbert, Andrew R. Halford, Tom Heintz, James Hewlett, J. Hobbs, Whitney C. Hoot, Peter Houk, Lyza Johnston, Michelle A. Johnston, Hajime Kayanne, Emma Kennedy, Ruy Kenji Papa de Kikuchi
Abstract
Ocean warming is increasing the frequency, extent, and severity of tropical-coral bleaching and mortality. During 2014-2017, marine heatwaves caused the Third Global Coral Bleaching Event. We analyze data from 15,066 reef surveys globally during 2014-2017. Across all surveyed reefs, 80% and 35% experienced moderate or greater (affecting >10% of corals) bleaching and mortality, respectively. We assess the global extent of coral bleaching and mortality by applying bleaching response curves calibrated from surveyed reefs to predict bleaching globally, based on comprehensive remote-sensing of heat stress. These models predict that 51% and 15% of the world's coral reefs suffered moderate or greater bleaching and mortality, respectively, during one or multiple years, surpassing damage from any prior global coral bleaching event. Our findings demonstrate that the impacts of ocean warming on coral reefs are accelerating, with the near certainty that ongoing warming will cause large-scale, possibly irreversible, degradation of these essential ecosystems. With heat stress levels during this event surpassing those observed previously, the National Oceanic and Atmospheric Administration developed more extreme Bleaching Alert levels that are now being used during the ongoing Fourth Global Coral Bleaching Event.