Effect of relative sea level rise on salt marsh change

Abstract

Salt marshes are important coastal ecosystems that provide essential services such as storm protection and food provision. Understanding the fate of the marshes under accelerating rates of sea-level rise is therefore crucial. However, the global effect of relative sea level rise on marshes is still debated, and existing models remain unvalidated. Therefore, this study analyzes the global correlation between relative sea level rise (RSLR) and salt marsh change. Investigating the correlation on a global scale ensures that the findings can be applied to marshes worldwide, as unique local factors like sediment availability and tidal range make localized studies non-transferable. The results show that for each additional millimetre of RSLR per year, the salt marsh area is expected to decline by 0.02%. This correlation appears even stronger in deltaic regions, where sediment supply strongly controls salt marsh change. Furthermore, it is found that regions with macro tidal range show average marsh gain, whereas regions with meso and micro tidal range generally indicate average marsh loss. By conducting a global assessment and considering vertical land motion, this research tries to elaborate on earlier findings.