Loss of cultural world heritage and currently inhabited places to sea-level rise

The world population is concentrated near the coasts, as are a large number of Cultural World Heritage sites, defined by the UNESCO. Using spatially explicit sea-level estimates for the next 2000 years and high-resolution topography data, we compute which current cultural heritage sites will be affected by sea-level rise at different levels of sustained future warming. As indicators for the pressure on future cultural heritage we estimate the percentage of each country’s area loss, and the percentage of current population living in regions that will be permanently below sea level, for different temperature levels. If the current global mean temperature was sustained for the next two millennia, about 6% (40 sites) of the UNESCO sites will be affected, and 0.7% of global land area will be below mean sea level. These numbers increase to 19% (136 sites) and 1.1% for a warming of 3 K. At this warming level, 3–12 countries will experience a loss of more than half of their current land surface, 25–36 countries lose at least 10% of their territory, and 7% of the global population currently lives in regions that will be below local sea level. Given the millennial scale lifetime of carbon dioxide in the atmosphere, our results indicate that fundamental decisions with regard to mankind’s cultural heritage are required.