Cook Islands

By the close of this century, the Cook Islands is most likely to be a smaller, warmer, and more lightly-visited nation than it is today, but also a more deliberate one — a country that has narrowed its tourism economy around two islands, professionalised its environmental governance, and made a generational decision about whether the ocean beneath its feet is best left alone. The threads that will weave that future are already visible in 2026, and they are tightening around three knots: a resident population that keeps drifting toward New Zealand, a lagoon ecology that has been managed rather than restored, and a seabed-minerals industry sitting in the wings of the Marae Moana marine park.

The demographic picture is the most under-discussed risk. The resident population now sits at roughly 17,000, and quarterly fluctuations have more to do with visitor flows than with births and deaths. Yet there are already roughly five times as many Cook Islanders living in New Zealand as in the islands themselves, and another large community in Australia. United Nations medium-fertility projections see the resident population continuing to drift downward through the century, toward something on the order of 8,000 to 11,000 by 2100. The political consequence is profound. Cook Islands tourism, which currently runs at a visitor-to-resident ratio of roughly ten to one — among the highest in the Pacific — will most likely widen that gap further. Filipino, Fijian, and Indian guest workers, who already form an important share of the tourism workforce, will probably become a quarter to two-fifths of the resident labour force, while climate-displaced Pacific Islanders from Tuvalu, Kiribati, and Tokelau may add a smaller but symbolically important inflow.

The climate trajectory most likely to play out is the middle-of-the-road one: roughly 2.7 degrees Celsius of warming and a sea-level rise of perhaps half a metre to three-quarters of a metre by century's end. For the volcanic southern islands — Rarotonga rising to 652 metres at Te Manga, Aitutaki anchored by its 124-metre volcanic remnant — the verdict is "manageable but transformative." The country will not lose its inhabited land. What it will lose, segment by segment, is the present coastal building line: stretches of the Te Ara Nui ring road, low-lying portions of resort frontage, parts of Avatiu harbour, and the approaches to Rarotonga International Airport. Coastal defence will become a chronic line item in the national budget, and several sections of the ring road will most likely require either elevated reconstruction or controlled retreat inland by mid-century.

The northern atolls face a far harsher reckoning. Penrhyn, Manihiki, Rakahanga, Pukapuka, Nassau, Suwarrow, and Palmerston rarely rise more than four metres above the sea. Cyclone Martin's destruction of Manihiki in 1997 remains the historical benchmark, and the expectation that a higher proportion of cyclones will reach Category Three or above means even moderate sea-level rise compounds dangerously with surge. By 2100, the Northern Group is most likely to function as climate-stressed cultural homelands and marine science outposts rather than as everyday settlements. Penrhyn and Manihiki may retain seasonal pearl and cultural populations of perhaps a hundred to three hundred residents each. Pukapuka and Rakahanga slide toward voluntary managed retreat options into Rarotonga and New Zealand. Black-pearl culture, threatened additionally by ocean acidification dropping surface pH from about 8.05 today to roughly 7.85, survives as a heritage industry assisted by oyster-health monitoring rather than as a major export earner.

The hard truth at the heart of the tourism economy is that the country's hotspots and its pollution hotspots are the same places. Muri Lagoon on Rarotonga — which alone accounts for roughly a quarter of the island's tourist bed-nights — has been managed rather than restored since the 2015 algal bloom national disaster. On-site septic systems leaching nutrients into the porous coral-sand aquifer remain the leading cause of trouble; a centralised reticulated wastewater system has been in design for years without being built, and a 2020 anoxic event showed the system has continued to fail intermittently. Aitutaki, the second engine of the tourism economy, is now displaying similar symptoms around Arutanga, where post-2021 harbour dredging stagnated channels and smothered sections of reef. Until reticulated sewerage is operational on both islands and visitor carrying capacities are enforced, the eutrophication-bleaching-starfish-sediment synergy will keep grinding the lagoons down. Add a multi-year crown-of-thorns starfish outbreak and the Northern Cooks reaching Bleaching Alert Level 2 during the 2023–2025 global bleaching event, and the most credible 2100 reef outcome looks less like restoration and more like actively-managed refugia of heat-resilient coral genotypes, scaled from the Titikaveka nursery model where roughly 80 percent of bleached corals recovered during the April 2024 heat wave.

The single largest wildcard sits beneath the EEZ. Three exploration licences over a 1.9-million-square-kilometre marine park, JORC-compliant resource estimates of around 6.7 billion tonnes of polymetallic nodules, and a global energy transition that is hungry for cobalt, nickel, manganese, and rare-earth elements: the financial logic is severe. Exploration was extended in 2026 to 2032, and the most likely path is a conditional, phased "go" decision somewhere in the 2030s or early 2040s. Royalties could become a parallel revenue stream of comparable magnitude to tourism within a generation. The cost is a permanent change to the country's clean, green marine brand, a more strenuous diplomatic balancing act between New Zealand, China, and the United States, and the prospect that legacy environmental liabilities — sediment plumes, abyssal-fauna impacts — become a constant late-century exposure even after battery chemistries shift and nodule demand recedes.

Aviation is the country's most stubborn external problem. Sustainable aviation fuel still accounts for a fraction of a percent of global jet fuel production, and the practical implication for an island nation entirely dependent on long-haul flights from Auckland, Sydney, and Los Angeles is that real ticket prices will most likely rise substantially in real terms by mid-century. That price signal restructures the visitor profile toward fewer, higher-spending, longer-staying travellers — exactly the strategy the country's tourism agency has been articulating. Annual arrivals are most likely to peak somewhere between 200,000 and 220,000 in the late 2030s or early 2040s, then settle back toward 120,000 to 160,000 by 2100, with average per-visitor spending substantially higher in real terms.

Artificial intelligence is most likely to act in the Cook Islands less as a tourism technology than as an environmental instrument. The country is small enough for sensor saturation to be affordable, its problems are highly tractable to computer vision and remote sensing, and central decision-making is unusually concentrated. Cheap moored sensors and autonomous underwater vehicles will monitor lagoon chlorophyll and dissolved oxygen in real time. Automated detection-and-inject systems for crown-of-thorns starfish will most likely supplement the volunteer dive teams that currently spear them. Satellite-AIS vessel-anomaly detection will become the de facto enforcement layer of Marae Moana, since no single patrol boat can credibly police nearly two million square kilometres. Machine-learning-assisted genotype selection will scale coral nurseries. Language-model tools will support the revitalisation of Cook Islands Māori and its dialectal variants, although the centre of gravity for that language will remain in the diaspora rather than at home.

The traditional governance institutions — the House of Ariki, the Koutu Nui, the broader aronga mana — will most likely retain and probably expand their conservation authority, particularly through the ra'ui system that places marine and terrestrial resources under temporary tapu. Peer-reviewed monitoring has already shown ra'ui sites producing fish aggregations many times the density of unprotected reefs; one estimate at Aro'a Lagoon put the increase at roughly a hundredfold over two decades. The fragility of the system is its lack of statutory teeth, which a Marae Moana amendment is the obvious vehicle to fix. The most credible 2100 governance picture is a hybrid customary-statutory regime in which Koutu Nui-nominated guardians enforce ra'ui under codified powers, while elected institutions handle day-to-day governance and traditional leaders retain ceremonial and conservation roles.

Pulling these threads together, the most likely Cook Islands of 2100 is a country of perhaps ten thousand permanent residents serving roughly 140,000 visitors a year on a higher-yield, lower-volume tourism model concentrated on Rarotonga and Aitutaki. Its electricity is largely decarbonised. Its lagoons are cleaner than they were in 2025 but carry cumulative damage that has not fully reversed. Its reefs survive as actively-managed refugia rather than as the abundant assemblages of the 1980s baseline. Its Northern Group atolls have largely become seasonal cultural homelands, with managed retreat to Rarotonga and New Zealand a completed reality rather than a prospect. And somewhere offshore, beyond the horizon of the marine park's no-take zones, a generation of seabed mining will have come and gone, leaving behind a sovereign wealth fund, a more complicated diplomatic posture, and a quietly altered conscience about what it meant to be a marine-conservation nation in the twenty-first century.