New research says hundreds of islands in the Pacific are growing in land size, even as climate-related sea levels threaten the region.
The main point:
- Coral reef sediments are responsible for increasing land area
- The waves sweep up the sediment and deposit it on the islands
- However some islands are becoming smaller due to coastal erosion
Scientists at the University of Auckland found atolls in Pacific countries in the Marshall Islands and Kiribati, as well as the Maldives archipelago in the Indian Ocean, have grown by 8 percent in the past six decades despite rising sea levels.
They say their research can help climate-prone countries adapt to future global warming.
Scientists are using satellite images of the islands as well as field analysis to track these changes.
Coastal geomorphologist Dr Paul Kench said coral reef sediments were responsible for building the islands.
Dr Kench said in areas where coral reefs were healthy, enough sediment was produced to make the islands grow.
“The majority of the islands in each of these countries have become larger or remain very similar in size,” he said.
“So, you know, one of the great things about this job is that the islands are actually quite physically dynamic.”
Healthy coral reefs are the key to growth
Coastal erosion due to rising sea levels is considered a major threat to many Pacific communities, with some witnessing coastlines receding.
Dr Kench said about 10 percent of the islands captured in the study were getting smaller in size.
He said a better understanding of which islands are growing and which are experiencing erosion could help Pacific countries adapt to climate change.
“That gives island nations the power to think about adaptation strategies, about where you focus on further development, and you will probably select islands that we can show are really growing in size,” he said.
Dr Kench said more work needs to be done to understand other factors affecting the growth or reduction of Pacific islands.
One of the concerns is the degradation of coral reefs due to global warming.
“Even though we can see healthy sites, and the sediment production that creates the islands is still happening, there should be some concern in locations where coral reef conditions are poor,” he said.
“So we are not suggesting here with any imagination that the island should not be worried.
“I think one of the messages from the work we’re doing is that island outcomes and prognosis will vary widely from site to site.”