The process of atoll island accretion. Photo: Trends in Ecology & Evolution
Coral atolls are not necessarily doomed to drown but could outgrow sea level rise, a new scientific study argues.
Lead author Sebastian Steibl from the University of Auckland said the article addresses the common narrative that low lying coral atolls do not have a chance of surviving rising seas caused by climate change.
"We argue that this is dangerously misguided and that there are many opportunities out there to locally restore the resilience of atolls," Steibl said.
"If we already assumed that there's nothing we can do about it and these are doomed and drowned, we're not even looking for place-based opportunities and helping the communities to stay on their island," he said.
The world's 320 tropical coral atolls are made up of thousands of islands and are home to millions of turtles and seabirds.
According to the study, these islands are naturally growing up to one centimetrer a year by accreting sediment - enough to outpace most predictions of sea level rise.
Steibl said atolls are made up of biological materials - unlike volcanic rocks that sit statically in the ocean.
"From different studies that looked at the island growth over the last half century, they found that over 88 percent of the atoll islands that they studied kept growing at pace with rising sea levels, and during that time period - depending on the region - sea levels had already risen by over half a metre."
Steibl said coral reefs around the island are producing sediment when coral is degraded by fish or other means, it then accumulates on the island by getting caught in vegetation.
He said reefs were sediment factories and waves are a conveyor belts moving the sediment to the island.
"This interplay helps or allows these islands to grow upward."
Steibl said healthy reefs are essential for islands to continue to grow.
Reef health is also at risk of climate change from ocean acidification and warming oceans.
Steibl said reducing greenhouse gas emissions is still essential but reducing local scale impacts, like sewage flow in the sea and overfishing, improves reef health.
"There's a lot of these local stresses where we can actively control or help the reefs to become more resilient.
"We have to rethink the way we approach atolls and start to look into local opportunities for place-based solutions to help these islands and the humans that live on these islands," he added.
The study, titled Rethinking atoll futures: local resilience to global chanllengs can be found here.