Local-scale projections of coral reef futures and implications of the Paris Agreement

Ruben F van Hooidonk (1) , Jeffrey F Maynard (2) , Jerker Tamelander (3) , Jamison F Gove (4) , Gabby F Ahmadia (5) , Laurie Raymundo (6) , Gareth Williams (7) , Scott F Heron (8) , Serge Planes (9)

1 AOML - NOAA Atlantic Oceanographic and Meteorological Laboratory
2 CRIOBE - Centre de recherches insulaires et observatoire de l'environnement
3 United Nations Environment Programme
4 Ecosystems and Oceanography Program
5 World Wildlife Fund
6 Marine Laboratory
7 School of Ocean Sciences
8 Marine Geophysical Laboratory
9 LabEX CORAIL - Laboratoire d'Excellence CORAIL

Increasingly frequent severe coral bleaching is among the greatest threats to coral reefs posed by climate change. Global climate models (GCMs) project great spatial variation in the timing of annual severe bleaching (ASB) conditions; a point at which reefs are certain to change and recovery will be limited. However, previous model-resolution projections (~1 × 1°) are too coarse to inform conservation planning. To meet the need for higher-resolution projections, we generated statistically downscaled projections (4-km resolution) for all coral reefs; these projections reveal high local-scale variation in ASB. Timing of ASB varies >10 years in 71 of the 87 countries and territories with >500 km 2 of reef area. Emissions scenario RCP4.5 represents lower emissions mid-century than will eventuate if pledges made following the 2015 Paris Climate Change Conference (COP21) become reality. These pledges do little to provide reefs with more time to adapt and acclimate prior to severe bleaching conditions occurring annually. RCP4.5 adds 11 years to the global average ASB timing when compared to RCP8.5; however, >75% of reefs still experience ASB before 2070 under RCP4.5. Coral reef futures clearly vary greatly among and within countries, indicating the projections warrant consideration in most reef areas during conservation and management planning.

Keywords: C0P21; Paris agreement; Climate change; coral reefs conservation

Domains: Environmental Sciences; Global Changes; Environmental Sciences; Biodiversity and Ecology

Ruben F van Hooidonk, Jeffrey F Maynard, Jerker Tamelander, Jamison F Gove, Gabby F Ahmadia, et al.. Local-scale projections of coral reef futures and implications of the Paris Agreement . Scientific Reports, 2016, 6, pp.39666. ⟨10.1038/srep39666⟩. ⟨hal-01441969⟩