"IUCN: 96% of Coral Reef Ecosystems Face Collapse by 2075"

On October 22, the International Union for Conservation of Nature published the first global assessment of shallow-water coral reefs under its Red List of Ecosystems, and the headline number is stark: 122 of the 127 reef ecosystems assessed — 96 percent — are classified as Critically Endangered, the highest risk category short of collapse itself. The assessment covers 188,362 square kilometres of shallow, sunlit reefs in more than 80 countries and territories, and the ecosystems in the top risk category account for 99.8 percent of that total area. Only one, the Western Galápagos, is already classified as Collapsed.

It is worth being precise about what collapse means here, because the word invites a picture of reefs already dead, and that is not what the assessment says. Most of these reefs still have living coral. Collapse means the system stops being a coral reef in any functional sense: the hard corals that build the structure nearly disappear, and algae, rubble and sponges take over, along with the fish, fisheries, tourism and wave-breaking protection that depended on the living structure. The classification is also a forecast, not a photograph. Judged only on observed changes over the past 50 years, 30 ecosystems — 24 percent — reach the Critically Endangered category. It is the projected heat stress that takes the number to 122. Under a middle-of-the-road emissions pathway, roughly 2.7 degrees of warming by 2100, heat stress alone puts 95 percent of the assessed ecosystems in the top category. So the assessment is a conditional sentence: if the warming arrives as projected, the reefs as we know them do not survive it.

The timing was deliberate. The findings were announced in the middle of CBD COP17, the UN biodiversity conference running October 19–30 in Yerevan, Armenia, where governments are conducting the first global review of the Kunming-Montreal framework — the 2022 deal that promised to protect 30 percent of land and sea by 2030. Judged against that promise, the ocean numbers are embarrassing. A Greenpeace report published days before the conference found that only about 3.5 percent of the ocean is fully or highly protected, and that at the current pace of new designations, reaching 30 percent would take until 2289. The same report identified 17 sites in the Atlantic high seas that should become sanctuaries, noting that 80 percent of the areas where leatherback turtles face medium-to-high bycatch risk lie outside any proposed protection at all.

What has changed since the last time these numbers were rehearsed is that the legal machinery to act on them now exists. The High Seas Treaty — the BBNJ agreement covering the two-thirds of the ocean beyond national jurisdiction — entered into force on January 17, 2026, after its 60th ratification last September, and now binds more than 80 countries. It is the first treaty that can create marine protected areas in international waters. Its first Conference of the Parties is still ahead, which means the mechanism for designating those 17 Atlantic sites, and others like them, is real but untested. Nothing has been designated yet.

That is where my attention settles, because the pattern in ocean conservation has been depressingly consistent: the science arrives, the targets are adopted, and then the designations crawl. The IUCN assessment gives the negotiators in Yerevan something previous conferences lacked — a shared baseline for every major reef system, measured the same way, against which future progress or failure can be checked. And the treaty gives them a place to put protection that is not inside any country's waters. The question COP17 has to answer is not whether reefs are in danger; that question is now settled to the point of tedium. It is whether the machinery built for this exact purpose will produce its first result quickly. I think it will: I expect at least one high-seas marine protected area to be formally designated under the High Seas Treaty before the end of 2027. The candidate sites are already mapped, the treaty is in force, and the political cost of a first designation has never been lower. The honest uncertainty is institutional, not scientific — a first Conference of the Parties has to set up its own procedures before it can approve anything, and first meetings are where good intentions go to be procedurally delayed. If the designation slips into 2028, that will tell us something too: that we built the lifeboat and then spent a year arguing about the seating plan.