Dead corals in Tuvalu

IEF member Austin Bowden-Kerby wrote from Tuvalu on 27 August about the extreme loss of corals in Tuvalu, an island nation in the mid-Pacific consisting entirely of atolls, rings of coral reefs and islets around a large lagoon, but no more than a few metres above sea level.

Austin said that in 2018 Tuvalu had the most amazing coral reefs he had ever seen, with thickets of heavy branched Acropora staghorn corals towering 5+ meters high. Tuvalu then had the most pristine reefs he had seen since the 1970s, crowded with fish.  But now they stand as dead thickets of scum-covered coral skeletons. Fish clean patches of the dead branches, but the colourful plankton feeding fish are gone. The coral reefs have ALL died - technically only 99.99% both inside the lagoon and on the ocean facing sides - they all bleached and died in the severe marine heat wave of 2024. It has been well over a year now, but no one has informed the world.

In two hours of searching, dragged on a rope behind the boat, he saw just one small-branched colony of Acropora, three small Pocillopora, and some sparse Porites found among the wasteland. Everything was DEAD as far as the eye could see.

This was extinction level bleaching and all coral species but Porites and perhaps Pocillopora are now ecologically and reproductively extinct in Tuvalu, and many coral species are likely biologically extinct as well. But if two colonies or even a hundred of a species have survived, they will not produce offspring as they will be too far from any others of their kind. There are no coral reefs upcurrent to the east from which to receive coral larvae, so recovery looks unlikely. And the animals that eat live corals will eventually have their way. Tridacna giant clams also seem to be extinct, since like corals they also depend on zooxanthellae (symbiotic algae) for food.

Austin was shocked and badly impacted to see such a horrific change. Simply devastating - someone said that it looked just like Gaza. On a technical level, the dominant Acropora corals are completely gone. He did find eight Acropora colonies, but all of them were part of the 2018 coral nursery he created by moving ~100 corals from the hot pocket reefs to cooler waters. This proves that local scale translocation works and that the corals remained heat resistant for seven years. Also there was a 12cm fragment of a wild purple Acropora right beside the nursery, which was strange as that is the only live Acropora coral that he found on the reef. This coral may have acquired some of the heat adapted symbiotic algae from the nursery corals, perhaps, he guesses, shared on the teeth of a coral-eating butterfly fish. And judging by the predation marks from butterflyfish and parrotfish, post-bleaching predation might have eliminated any remnant corals. The nursery site had abundant sharks, and so it has fewer parrotfish that eat corals. There may be surviving Acropora corals in reef passes where heat adapted coral larvae may have escaped from heat adapted coral populations of the lagoon, and where the sharks could have prevented post-die off death due to the vastly increased predator to prey ratio. There are a few remaining corals of the resistant genera Porites and Pocillopora, but very few and far between. Many are pocked by butterfly fish predation. The only reefs comparable to this level of destruction are in parts of Kiribati, which died in 2014-15, as well as parts of the Caribbean.

On 28 August, Austin spent several hours again in the water, and saw a few scattered Porites and Pocillopora colonies and a few massive Pavona among the carnage. This may be many thousand at the scale of the reef, but the precious and vulnerable Acropora corals that formerly dominated the reefs are now gone.

NOAA predictions put Tuvalu at condition 3 bleaching, but this impact was much much worse, similar to the condition 5 bleaching that hit Kiritimati Atoll in 2015.

It has been a year and a half since the massacre of the very system that created the nation, Austin wrote, but the government has been silent. The mother of the nation has been murdered by the fossil fuel industry. And the nation is distracted by their phones and has been seduced by foreign aid, air conditioned offices, and near constant travel to international meetings that produce nothing but words. He met with Tuvalu Minister Simon Kofe, who as Foreign Minister addressed the world at COP26 in 2021 while standing in water (see The Guardian article). He and his government were unaware. The plan now is to get him and the other ministers and parliamentarians into the water to see first hand the horrific destruction.

Much could be done to search far and wide looking for survivors to reboot recovery (as Austin has done elsewhere). This will depend on the sons and daughters of this nation - a nation that was created and nurtured by a reef, yet that connection has now seemingly been forgotten. And much the same could be said for Kiribati.

The evidence is now clear - the planet's climate is already over the tipping point for coral reefs, and even if we stop the carbon pollution now, the scientific consensus is that virtually all coral reefs will be dead within 25 years. Our goal must be to prevent that extinction via carrying out emergency rescue measures for coral species. Even then it will be touch and go. Climate change is a serial killer: in the Pacific the first victim was Kiribati in 2015, and then it killed the reefs of Tuvalu in 2024, and it is now hitting the Solomon Islands and PNG, and after that will be Samoa and Vanuatu and lastly Fiji and New Caledonia. Our only defense is to buy more time for the corals by moving heat adapted corals into cooler waters locally, while our long term solution will of course be a transformation of energy production systems and a rewilding of the planet so that carbon is reabsorbed into the biosphere.

Austin asked us to be thankful for what corals we have left in our own nations, and work to ensure their survival, because Tuvalu and Kiribati could soon be our future if we are not well prepared.

IEF president Arthur Dahl, also a coral reef specialist, read in the Guardian Weekly of 22 August a six-page feature article by Atul Dev entitled "How to leave a sinking nation" about Tuvalu and its rising sea level. It mostly discusses the challenges and options of migration as sea level rise makes atolls uninhabitable. But it also describes some local opinion that the atolls are dynamic, eroding in some places and accreting in others. It also quotes geomorphologist Paul Kench, now professor at the National University of Singapore, who studies atoll dynamics, with some eroding, but Tuvalu's land area increasing 2.9% since the Second World War. His 2018 paper of coastal changes in Tuvalu showed that, out of 101 islets, 73 had accreted 80.7 hectares, and 28 eroding 7.24 hectares.

Arthur was formerly ecological advisor to all the Pacific Island countries. He has visited Tuvalu and the other atoll countries, and has long warned about this risk and written about it on the IEF website. He has often thought that sea level rise might permit the upward growth of atoll reefs, just as they grew up in the past from submerging volcanoes. But if the sea level rise was too rapid, the reef could not keep up, and might only later catch up, too late for the human population. Of course that assumes a healthy coral reef. With the die-off Austin has described, the atolls are doomed to drown. The past is no longer a guide to the future. Nature cannot help.

IEF member Carol Curtis, who lived for many years on atolls in the Marshall Islands, has read about the increase of land in Tuvalu. Assuming the land is no higher than what exists today, as the sea rises, the groundwater rises too, and since, at least in the Marshalls, it is less than a metre below land level, during king tides it can be less.  So when this water, that is becoming more and more brackish with each passing year, hits the very shallow root systems of all the vegetation, then it will all die and people will be living on pieces of sand, whether the atoll islands are growing or eroding. This will destroy the atolls long before the ocean washes over all the land, and the four atoll nations disappear.

Austin has published two papers on this tragic situation with coral reefs and the need for new efforts to save corals. See his 2024 Reefs of Hope paper: https://www.mdpi.com/2673-1924/4/1/2 and a new paper published on 19 September 2025: https://www.mdpi.com/2071-1050/17/18/8430/pdf.

Austin has prepared an illustrated report on the coral reefs of Funafuti, Tuvalu, as observed flourishing in 2023 and dead in August 2025, which can be downloaded here. It is also published at https://doi.org/10.13140/RG.2.2.28091.48167.

SOURCES: emails from Austin Bowden-Kerby, Arthur Dahl and Carol Curtis, 27-28 August and 9 September 2025.
ADDITIONAL SOURCE: https://www.theguardian.com/news/2025/aug/14/how-to-leave-a-sinking-nat…