I can’t pretend everything will be ok.
As I write this, the waters of South Australia are choking, but unless you are paying particularly close attention, you probably missed it.
High autumn sea and air temperatures, still winds and still waters have led to an unprecedented outbreak of Karenia mikimotoi. The dinoflagellate algae bloom is slaughtering virtually all animal life in St Vincent Gulf, directly adjacent to the South Australian capital of Adelaide.
Millions upon millions of animals have died in this single event. Their deaths are directly linked to the combustion of fossil fuels through rising temperatures — the sea temperature in the area is currently 2.5°C above normal — and likely also through the increasing ocean acidity — driven by the absorption of excess carbon dioxide from fossil fuels and other sources into the water. Increased ocean acidity has been demonstrated to both facilitate the growth of Karenia blooms and to make them more toxic.
The images of dead and bloated ocean life — snails, cuttlefish, octopuses, sharks, fish, worms, crabs, eels, and so much more — are difficult to look at even by someone whose heart has been hardened by seeing too much climate catastrophe. Over 200 different species have been recorded as killed from this vast toxic cloud, which has been reported as being around 4,000 square kilometres (1,500 square miles) in size, and in some places up to 20 metres (65 feet) deep.
This region forms a small part of the Great Southern Reef, a continental-scale haven of biodiversity stretching right across the bottom of Australia from Perth to Sydney. The rocky kelp forest totals 8,000 kilometres, or about 5,000 miles. Stretched out, it would extend one-fifth of the way around the planet.
In all its vastness — and despite its relative anonymity compared to other natural wonders — it is being fundamentally diminished by climate change, as ocean warming, the increasing acidification of the waters and shifts in critically important currents take their toll.
In sections of the Great Southern Reef, immense kelp forests form the foundation of the reef, creating the landscape by providing a foundation that a wild array of other life can build upon. Long before Karenia arrived in St Vincent Gulf this kelp began to struggle and die.
2025 hasn’t been a good year for Australia’s marine life.
In the first two weeks of the year, a mass fish kill was reported at Gnoorea, near Karratha in north-western Western Australia. A 9 kilometre (5 mile) stretch of beach was lined with the bodies of wrasse, puffer fish, dory and rock cod — among many others — with the Western Australian government estimating that 30,000 fish washed ashore. To put those numbers into perspective, imagine walking for two hours along the sand, passing three individual dead fish on the sand for every step you take. Then realise that this is just the dead fish that washed ashore. Many others will have been pushed in other directions by the waves and tides.
The proximate cause of the immense die-off was a marine heatwave that had been building in the area since early spring 2024. Driven by global heating brought about through the production and burning of coal, oil and gas, water temperatures off the coast were initially around 3°C (5.5F) above normal. In late December, this temperature anomaly increased to 4–5°C (7–9°F), rapidly pushing species beyond their natural limits, with unusual heat levels extending as much as 200 m (650 feet) below the surface.
There’s a sick irony to this particular event, sitting as close as it does to Western Australia’s catastrophically-enormous gas export terminals across the state’s north-west. Gnoorea beach, where evidence of the fish kill was at its largest, sits roughly halfway between Karratha — the home of Woodside’s Pluto and North West Shelf liquefied gas terminals —and Barrow Island — the home of Chevron’s Gorgon liquefied gas terminal and its failed carbon capture and storage operation. North West Shelf is the largest fossil gas export facility in one of the world’s largest seaborne gas exporters, and Gorgon is the country’s largest industrial greenhouse gas emitter.
Woodside has plans to expand both its Pluto and its North West Shelf facilities in coming years, further worsening the problem into the future. Our new environment minister is set to approve one of these expansions this week. [edit: he just did, hours after I published this piece.] At least it will be easy for applicants for work at the terminals to find their way to the job interview: just turn right at the pile of rotten fish.
Over the following months, Western Australia’s Leeuwin current — which runs southward along the state’s coast — dragged this pool of superheated water along the shoreline as a slow-motion disaster for life in the ocean.
Inevitably, this heat eventually hit the World Heritage-listed Ningaloo coast, and Ningaloo Reef. This vital system is of lesser worldwide renown than Queensland’s Great Barrier Reef, but no less precious, essential and unique. Unlike many of the world’s tropical coral reefs, to date Ningaloo Reef had largely avoided mass-bleaching events, and mass-mortality, that has wracked reefs elsewhere in the world.
But 2025 has proved that Ningaloo is not immune. As the marine heatwave that hit Karratha coast at the start of the year rolled south it has caused widespread bleaching across the reef and substantial mortality. Giant reef-building corals, some of which are centuries-old and have grown as tall as multi-storey houses, have turned porcelain white as trillions upon trillions of polyps expelled their primary food source in response to the stress of hot water. Given time, the corals can recover if the heat passes soon enough, and thankfully many will. However, at the time I write this in May, the abnormal heat has been sitting above the reef for several months. It is currently anticipated to sit above the region for at least another month before receding in earnest.
At this stage it isn’t possible to make a reliable estimate of the permanent damage to the reef of this single event, other than to say that there will be significant mortality. However, the combustion of coal, oil and gas is certain to make events like this recur. By the middle of the century, our best available science indicates that marine heatwaves like this will recur multiple times each decade. This is substantially less than the amount of time it takes reefs to recover from events such as this, guaranteeing the critically-important ecosystem’s long-term decline.
How much of this natural wonder survives in place of what exists today will be determined by how dramatically we reduce fossil fuel production. Without a shadow of scientific doubt — regardless of the action taken today — what remains will be poorer for the damage occurring today and much surely be lost for good.
Even if wealthy nations limit their fossil fuel use sufficiently to ensure that warming is limited to just 1.5°C above pre-industrial levels, it is anticipated that up to 90% of the world’s tropical coral reefs will be lost. Things get progressively worse the higher we permit temperatures to climb through our continued reliance on fossil fuels. At +2°C those permanent losses climb to 99%.
While Ningaloo had been relatively insulated from marine heatwaves before 2025, the same cannot be said for the Great Barrier Reef, sitting on the other side of the continent.
The world’s largest tropical reef extends 2,300 km (1,400 miles). That’s roughly the same distance as from London to Athens, or New York to Dallas. Australians have historically been both proud and protective of our reef. And with good reason. It is a staggeringly enormous piece of natural architecture, and the species diversity along its length is gazonkingly high, with thousands upon thousands of animal species present even before you begin to count the plants, fungi, bacteria and other life that make the reef its home.
In 2025, the Reef experienced severe and widespread bleaching for the eighth time. The first time mass bleaching was observed on the Reef was in 1998, and the events have been recurring with increasing frequency, with mass bleaching occurring in 2002, 2016, 2017, 2020, 2022, and 2024. And while the bleaching events have hit different parts of the reef at different times, the current rate of recurrence is far too frequent for proper recovery for much of the reef.
I have very little time for doomerism — and none at all for its adherents who are frequently as anti-scientific and conspiracy-laden as climate deniers — however, decades upon decades of growing fossil extraction and use mean that it is difficult to be anything other than fatalistic when it comes to imagining the future of the Great Barrier Reef. As with Ningaloo, whatever remains into the future will at best be vastly diminished compared to what exists today.
The loss of tropical coral reefs isn’t simply an issue of affective concern for the lives and well-being of fish and polyps. This has wide-reaching implications for human societies.
My habit, from years of climate education work is to step through all of these in an orderly fashion. Today, I feel like doing that is an insult: like reading through a patient’s tax statements while you sit beside them in hospital.
When I started to write this piece, I had a sense of something ill-defined but brilliant. I wanted to push through fear and grief to come to a place of rage, and action, and fight. Not for you, but for me. I have been trying to write that essay in various unpublished and unpublishable forms for fifteen years, because I need the fuel to keep fighting and to keep going. I won’t lie to you or myself by pretending that this might meet that brief.
I can’t pretend that everything will be ok, because everything won’t be ok.
That isn’t to say that those of you who are fighting should quit — you shouldn’t, and we need us — or that those of you who have been sitting on the bench should stay there — you shouldn’t, and we have never needed you more. For all that we are losing, and for all that we will lose, there will always be far more to save.
Home is always, always, always worth it.*
But to love what we have as if it ever mattered to us at all, we must bear witness and grieve. Today I bear witness.
On another day, I will come back to you with a message that helps you fight.
* Post script: You really should read this piece by Mary Annaïse Heglar. She is likewise always worth it.