In July 2016, Nan Madol was inscribed on the List of World Heritage in Danger, due to ongoing threats to its preservation, including natural forces, lack of resources, and climate change impacts.
The potential impacts of climate change and rising sea levels on Nan Madol are a growing concern for researchers and conservationists. As a low-lying coastal site, Nan Madol is particularly vulnerable to the effects of climate change, including increased erosion, storm surges, and saltwater intrusion. These threats pose significant challenges to the preservation of the site and its cultural heritage.
One of the primary consequences of climate change is the rise in sea levels, which occurs due to the melting of glaciers and ice sheets and the thermal expansion of seawater as it warms. Nan Madol’s coastal location and its low-lying structures make it particularly susceptible to the impacts of rising sea levels.
According to the Intergovernmental Panel on Climate Change (IPCC), global mean sea levels are projected to rise between 26 cm to 77 cm by the end of the 21st century under various emissions scenarios (IPCC, 2013). In the Pacific Islands, sea-level rise has been observed at an average rate of 3.1 mm per year between 1993 and 2017, which is higher than the global average of 2.9 mm per year (Australian Bureau of Meteorology and CSIRO, 2018).
As sea levels continue to rise, the risk of inundation and flooding during high tides and storm surges increases. This can lead to the destabilization of the basalt and coral structures, causing structural damage and the potential loss of invaluable archaeological artifacts. Furthermore, the increased frequency and severity of storm surges can exacerbate these impacts, resulting in more extensive damage to the site over time.
Increased Erosion
Another impact of climate change on Nan Madol is the increase in erosion, which can be attributed to changing weather patterns, such as more frequent and severe storms, as well as rising sea levels. Increased wave action and storm surges can accelerate the erosion of the site’s islets, undermining their structural integrity and leading to the collapse of buildings and other features.
In addition to the direct physical impacts of erosion, the loss of soil and vegetation from the site can also have detrimental effects on the site’s ecological and cultural values. As the soil erodes, it exposes previously buried archaeological artifacts to the elements, increasing their vulnerability to damage and decay. Moreover, the loss of vegetation can negatively affect the site’s aesthetic appeal and disrupt the local ecosystem, leading to a decline in biodiversity and the loss of habitat for various species.
Rising sea levels and the increased frequency of storm surges can result in saltwater infiltrating the site’s freshwater sources, such as wells and springs, leading to contamination.
Saltwater intrusion can also cause damage to the site’s basalt and coral structures by accelerating the corrosion process. The increased salinity levels in the water can lead to chemical reactions with the basalt and coral materials, causing them to weaken and deteriorate more rapidly. This can compromise the structural integrity of the site’s buildings and other features, making them more susceptible to collapse and other forms of damage.
