Scientists are increasingly arguing that some of the world's most vulnerable islands may not be able to engineer their way out of rising seas alone. Instead, the answer may lie in rebuilding the ecological systems that once helped these places grow naturally: seabird colonies that fertilize soils, native vegetation that traps sediment, and coral reefs that generate the sand and rubble needed to sustain island platforms.
Nature as Infrastructure
The idea is gaining traction because many atolls and low-lying islands are not static landforms. They are dynamic systems shaped by waves, currents, storms and biological activity. When those systems are intact, islands can sometimes keep pace with gradual sea-level rise by accumulating sediment and reshaping their shorelines. When they are degraded by development, invasive species, overfishing or reef loss, that natural capacity weakens.
Rewilding, in this context, is less a conservation slogan than a form of climate adaptation. Restoring seabird nesting grounds can return nutrients to island soils, supporting denser plant growth. Native plants can stabilize dunes and coastlines, reducing erosion during storms. Healthy coral reefs can dissipate wave energy before it reaches the shore, while also producing the carbonate material that helps form beaches and reef islands. Together, these processes can improve the odds that an island remains habitable even as oceans rise.
The concept is especially relevant for atoll nations and small island states, where land elevation is often measured in meters, not tens of meters. For these communities, the stakes are existential: freshwater lenses, housing, ports, roads and cultural sites all sit close to the waterline. Traditional adaptation strategies such as seawalls, breakwaters and land reclamation can be costly, ecologically disruptive and, in some cases, only temporarily effective.
Reefs, Birds, Sediment
The ecological logic behind rewilding is straightforward, but its implications are broad. Seabirds transport marine nutrients inland through guano, effectively linking ocean productivity with terrestrial growth. That nutrient flow can transform sparse, erosion-prone ground into more resilient habitat. Native coastal plants, meanwhile, act as living barriers that slow wind and trap sand. On reef-fringed islands, coral ecosystems can function as offshore breakwaters, reducing the force of incoming waves and helping preserve the very sediments that build beaches.
This matters because sea-level rise is not only a question of water height. It is also a question of whether islands can vertically accrete fast enough to remain above the tide line. In the best-case scenario, healthy ecosystems help create a feedback loop: reefs generate sediment, vegetation holds it in place, and birds enrich the land so plants can thrive. That loop can be broken when reefs bleach, birds disappear or native habitats are replaced by hardened shorelines and invasive species.
The approach is not a substitute for emissions cuts, and researchers are careful not to oversell it. If warming continues unchecked, even the most intact island ecosystems may struggle to adapt to faster sea-level rise, stronger storms and ocean acidification. But rewilding could buy time, reduce vulnerability and preserve options for communities that have limited room to retreat inland.
Adaptation With Limits
For policymakers, the appeal of rewilding is that it aligns climate adaptation with biodiversity restoration rather than forcing a choice between them. It can also be more affordable over the long term than repeated engineering fixes, particularly in remote island settings where construction materials and maintenance are expensive. Yet implementation is complex. Restoring reefs requires water quality improvements and fisheries management. Rebuilding seabird populations may depend on predator control and protected nesting sites. Native plant recovery can be undermined by grazing, land clearing and saltwater intrusion.
The broader lesson is that climate resilience on islands may depend as much on ecology as on infrastructure. Where ecosystems remain functional, they can act as a form of natural capital, helping islands absorb shocks and adapt to changing coastlines. Where they have been stripped away, the physical land itself becomes more fragile.
As sea levels continue to rise, the question is no longer whether islands need adaptation. It is what kind of adaptation will last. Rewilding offers one of the few strategies that can simultaneously strengthen shorelines, restore biodiversity and preserve the natural processes that built these islands in the first place.