Impacts of marine heatwaves on tropical western and central Pacific Island nations and their communities

Marine heatwaves can have devastating impacts on marine species and habitats, often with flow-on effects to human communities livelihoods. This is of particular importance Pacific Island countries that rely heavily coastal ocean resources, for which projected increases in future heatwave (MHW) frequency, intensity, duration could be detrimental across the region. In this study, we investigate MHWs tropical western central Ocean region, focusing observed MHWs, their associated impacts, projections using Coupled Model Intercomparison Project phase 6 (CMIP6) simulations under a low (SSP1–2.6) high (SSP5–8.5) greenhouse gas emissions scenario. Documented from “Moderate” mean intensity MHW events Fiji, Samoa, Palau, were categorised as “Strong” at peak, included fish invertebrate mortality coral bleaching. Based CMIP6 multi-model estimates, relative current baselines, are increase recent historical (1995–2014) values 10–50 days per year (dpy) region equivalent >100 dpy by 2050 scenario, > 200 nearer equator. Under Moderate intensities most 2050, >300 For intense “Extreme” category MHW, estimates range <1 climate >50 scenario 2050. contrast, <5 highlighting nations global more closely follow trajectory.