I'll look up the latest scientific projections on coral reef degradation so the claim can be checked against current evidence.The claim is broadly consistent with major assessments, but it compresses several different numbers and timeframes.
What the projections actually say?
IPCC assessments (SR1.5 and AR6) state with high to very high confidence that 70–90% of warm-water coral reefs are projected to be lost even if warming is limited to 1.5°C above pre-industrial levels. At 2°C the figure is >99%.
Those percentages refer mainly to loss of live coral cover and the collapse of coral-dominated reef ecosystems, not the complete disappearance of every limestone structure overnight.
A frequently cited earlier synthesis (Reefs at Risk Revisited) projected that combined warming and acidification would push more than 90% of reefs into “threatened” status by 2030, and nearly all by 2050, if emissions and local pressures continued on then-current paths.
Finer-scale thermal-stress modeling often produces even starker numbers: 95–99% of reef locations exceeding severe-bleaching thresholds every 5–10 years once global warming reaches ~1.5–1.7°C.
What “soon” means?
- Severe bleaching on most reefs in most years is projected for the 2030s–2050s under mid-to-high emissions.
- Several 2025 modeling studies of the Great Barrier Reef show a sharp drop in mean coral cover by ~2040 under all SSPs, with further collapse later in the century unless warming stays below ~2°C and adaptation keeps pace.
- High-emissions pathways produce near-total loss of coral cover on many reefs by 2080–2100.
Warming has already reached or briefly exceeded 1.5°C in recent years, so the lower-end IPCC scenario is no longer a distant hypothetical.
What has already happened?
Living coral cover has fallen by roughly half since the 1950s. Mass bleaching events are now more frequent and intense; the 2023 heatwave produced functional extinction of the two main Acropora species on large stretches of Florida’s reef. A fourth global bleaching event is underway. Reefs that lose most live coral also lose three-dimensional structure, fisheries habitat, and wave protection.
Important caveats
- Not every model assumes total ecosystem collapse. Some experimental and eco-evolutionary studies find that reefs can persist as altered, lower-cover, still-calcifying systems if warming is limited and some thermal adaptation occurs.
- Local refugia exist; a 2026 analysis identified substantially more climate-resilient reef area than earlier estimates.
- Local stressors (overfishing, pollution, poor water quality) still matter and can accelerate or slow the climate-driven decline.
- “90% degradation” is not a single official number for “this decade.” It is a reasonable shorthand for the combination of IPCC 70–90% loss at 1.5°C plus the 2030 “>90% threatened” figure.
Bottom line
Under trajectories close to current policy, most tropical coral reefs are projected to undergo severe degradation—loss of the majority of live coral and of classic reef ecosystem function—within the next few decades. Limiting warming well below 2°C, plus reducing local pressures and protecting remaining resilient sites, is what the literature identifies as the difference between widespread collapse and persistence in a changed form.