Quantifying impacts from natural hazards on World Heritage ‐ A case study from Frontiers of the Roman Empire: Hadrian’s Wall

Abstract

World Heritage (WH) sites are vulnerable to natural hazards, which have the potential to depreciate Outstanding Universal Value, including through erosion of its archaeological record. Safeguarding WH for future generations proves challenging as the effects of climate change are considered to be a risk multiplier to pre‐existing conditions. Heritage professionals raised concerns about the resilience of WH to climate change to the WH Committee in 2005, leading to the 2007 Policy Document on the Impacts of Climate Change on World Heritage. Despite over 15 years of progress, the effects of natural hazards on WH sites is still poorly understood due to inadequate methods for assessing impact. Currently, there is no protocol for quantifying impact in a rigorous scientific manner. The aim of this research was to combine advanced geospatial methods to quantify the impact of natural hazards on WH. This workflow was demonstrated on an at‐risk archaeological site from Hadrian’s Wall WH site where coastal dune erosion has been observed. By combining change detection and predictive modelling, historic coastal change of the study area was tracked c. 150 years into the past and forecasted 20 years into the future. The results showed that the dunes have receded in the area where the archaeology is most vulnerable by up to 50 m at a rate of 0.33 m/year +/‐ 0.02 m. The total area of detectable change from the continuous stretch of erosion along the same location was c. 7800 m2 with an estimated volume of sediment loss of c. 31000 m3. Future modelling predicted a further retreat of these dunes by c. 31 m, albeit with a large uncertainty (c. +/‐ 12 m), in 20 years’ time. In the event of the worst case scenario, if the dunes were left unmanaged and no archaeological mitigation were to be undertaken, this would result in a loss of over half of the current known extents of the archaeological remains buried within the sand dunes.