By Antonio Cerrillo
Five small Pacific islands have disappeared due to rising sea levels and coastal erosion, according to research published in the journal Environmental Rechearch Letters. The submerged islands are north of the Solomon Islands archipelago, where annual sea level rises of 7 millimeters have been recorded, more than double the global average. The islands swallowed up by the sea had an area of between 1 and 5 hectares and none of them was inhabited. They are (or were) Kale, Rapita, Rehana, Kakatina, and Zollies. The last four have vanished between 1962 and 2002, while Kale has recently disappeared.
In addition, six other small nearby islands have lost more than 20% of their surface between 1947 and 2014, and in two of them, which were inhabited, the villages have been destroyed, so their population has had to be relocated. In three islands (Hetaheta, Sogomou and Nuatambu), more than 50% of the surface has disappeared, due to a phenomenon that has accelerated especially since 2002.
A report attributes coastal erosion to wave energy and strong winds
To carry out their work, the scientists used, among other data, satellite images available since 1947 for a total of 33 islands. The Solomon Archipelago is made up of hundreds of islands that number 640,000 inhabitants and extend some 1,600 kilometers northeast of Australia. The study points out that coastal erosion (and the disappearance of the islands) is not only due to the rise in sea level, but also affects the high energy of the waves in localized areas, as well as the force of winds and other factors of marine dynamics, such as the Pacific Decadal Oscillation.
The severity and frequency of the rise in the sea in the Solomon Islands has forced the relocation of various population centers. In the village of Nuatambu, on the island of Choiseul, where 25 families live, half of the houses have been swallowed up by the ocean, rendering this area uninhabitable. The phenomenon has been occurring gradually for a few years, according to those affected tell the researchers. Many families have moved their residence to higher areas of this volcanic island, although the poorest families have simply rebuilt their houses in vulnerable areas of Nuatambu.
On the other hand, in the town of Mararo (to the east of the island of Malaita) relocations due to erosion have been organized, so that the entire population of the coast has moved into areas located more than 20 meters above the unevenness. from sea. “The sea began to enter inland; it forced us to go up the hill and rebuild our village far from the sea, ”94-year-old Sirilo Sutaroti, one of those relocated from Mararo, told the researchers.
The authors point out in a comment to their study that "this is the first scientific evidence that confirms the numerous anecdotal explanations throughout the Pacific regarding the dramatic impacts of climate change on the coast and the population." However, one of the researchers, Simon Albert, clarified yesterday to the press that there is no need to make a direct comparison between rising sea levels and climate change. He said that the rise in sea level had been influenced by exceptionally strong winds: and that, although these are part of a natural cycle, their recent intensification is related to atmospheric warming. "The key aspect is that these observations of the Solomon Islands are a warning of what will come regardless of whether what happened is due only to climate change or a sum of factors intervenes," he explained.
Previous studies had already highlighted a significant rise in the waters in this area of the Pacific (west), especially since 1990. The sea rose in the Solomon Islands about 15 centimeters between 1994 and 2014 (an average of 7 mm per year). And the projections indicate a rise of between 24 and 80 cm between 1996 and 2090, depending on the scenario drawn based on greenhouse gas emissions.
Annual sea rises of 7 mm or more are expected for this century. Furthermore, global mean ocean level rises will overlap with natural variability and tectonic movements, although these are not considered to be a primary determining factor in coastal erosion. The understanding of the factors that affect the rapid coastal retreat is classified by its authors as a crucial element to lay the foundations for future adaptation to climate change, as they add in the work.
Photo: Many islands in the Solomon Archipelago have their coasts below sea level (Peter Hendrie / Getty)