Atoll islands are made from sediment produced by corals, clams, snails, and varieties of algae that secrete carbonate. Under the right conditions, over time, fragments of coral skeletons, shells, and other sediments made by marine life are piled up by waves. Eventually, islands are formed – some large and some small. Atoll islands are home to a diversity of human cultures and are important refuges for a quarter of the world’s seabirds as well as numerous nesting sea turtles and tropical plants.
Rising sea levels – the rate of which has more than doubled over the past 30 years – are a mounting challenge for atoll islands. And by the end of this century, sea level is projected to rise between 11 and 40 inches, depending on the world’s actions with regard to greenhouse gas emissions.
The ability of atoll islands to persist depends on the health of their ecosystems and the extent to which their natural processes have been disrupted by human activity. To protect the most vulnerable islands, some researchers now propose using nature-based solutions – like restoring and protecting coral reefs and native forests.
Reclaiming seabird habitat can help reefs persist and restore the resilience of atoll islands. Seabird guano washes off islands and into reefs, providing nutrients that boost coral growth and fish populations.
Nature-based solutions cannot help the most urbanized atoll islands. These islands have already irreversibly lost their natural adaptive capacity. For those places, engineered approaches such as concrete seawalls are needed.
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How Natural Solutions Can Help Islands Survive Sea Level Rise
Photo, posted July 3, 2014, courtesy of Roderick Eime / MG Media via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio
