Change in mean sea level, being a long-term process, is an effect of climate change which will have an influence in coastal areas over this century and potentially beyond. For existing ports, these changes are important as mean and extreme water levels will change compared to those for which current infrastructure was designed. Similarly, new ports should expect such changes.
The rate and magnitude of future sea-level change vary with future emission scenarios, as well as being regionally and locally influenced by a range of other processes, such as gravitational effects, glacial isostatic adjustment (GIA) and deltaic subsidence. A global assessment of these changes contrasting different emission scenarios (using the IPCC’s lowest and highest Representative Concentration Pathways (RCPs)) indicates that sea-level change will have a significant impact within the design life of existing port infrastructure. In particular, mean relative sea-level rise will influence the height of extreme water levels and their associated return periods (e.g. with large effects in certain regions such as the Mediterranean).
Consideration of both mean and extreme changes within the planning and design process should ensure that these changing levels of risk can be addressed by design and/or scheduled maintenance/upgrade/adaptation for both existing and proposed port infrastructure, maintaining appropriate levels of safety and operation.