Sea Level Rise Swallows 5 (useless) Whole Pacific Islands

(scientificamerican.com)

- Sea-level rise, erosion and coastal flooding are some of the greatest challenges facing humanity from climate change.

Recently at least five reef islands in the remote Solomon Islands have been lost completely to sea-level rise and coastal erosion, and a further six islands have been severely eroded.

These islands lost to the sea range in size from one to five hectares. They supported dense tropical vegetation that was at least 300 years old. Nuatambu Island, home to 25 families, has lost more than half of its habitable area, with 11 houses washed into the sea since 2011.

- This is the first scientific evidence, published in Environmental Research Letters, that confirms the numerous anecdotal accounts from across the Pacific of the dramatic impacts of climate change on coastlines and people.

Previous studies examining the risk of coastal inundation in the Pacific region have found that islands can actually keep pace with sea-level rise and sometimes even expand.

However, these studies have been conducted in areas of the Pacific with rates of sea level rise of 3-5 mm per year – broadly in line with the global average of 3 mm per year.

For the past 20 years, the Solomon Islands have been a hotspot for sea-level rise. Here the sea has risen at almost three times the global average, around 7-10 mm per year since 1993. This higher local rate is partly the result of natural climate variability.

These higher rates are in line with what we can expect across much of the Pacific in the second half of this century as a result of human-induced sea-level rise. Many areas will experience long-term rates of sea-level rise similar to that already experienced in Solomon Islands in all but the very lowest-emission scenarios.

Natural variations and geological movements will be superimposed on these higher rates of global average sea level rise, resulting in periods when local rates of rise will be substantially larger than that recently observed in Solomon Islands. We can therefore see the current conditions in Solomon Islands as an insight into the future impacts of accelerated sea-level rise.

We studied the coastlines of 33 reef islands using aerial and satellite imagery from 1947-2015. This information was integrated with local traditional knowledge, radiocarbon dating of trees, sea-level records, and wave models. (Full Story)