Introduction
As seaports are located in the coastal zone, they are susceptible to climate change impacts such as rising sea levels and increased storminess. For seaports to still be able to operate under these changing conditions, a deeper understanding of potential climate change effects and adaptation options is needed.
Previous studies focus on climate change impacts for seaports at a regional scale, but there is a lack of understanding of the climate change impacts on specific, individual seaports. In addition, there is a lack of understanding of how seaports can accommodate or adapt to these impacts. We provide a conceptual framework for (i) quantifying risks for port operability and (ii) exploring adaptation strategies. Application of this framework to a specific port yields both the risks for port operability and potential climate change adaptation solutions. The framework is applied to a case study of the Port of IJmuiden in the Netherlands. While the framework is tested on a single case study site, it is believed to be a promising tool for exploring climate change risks and adaptation strategies for seaports worldwide.
Framework
The first step of the framework is a system analysis. Port operations and physical assets that are valuable to stakeholders and that may be vulnerable to climate change impacts are identified. The analysis is conducted by means of stakeholder interviews and desk research. The identified port operations and physical assets form the focus of the subsequent climate change risk assessment.
The second step involves translating greenhouse gas emission scenarios into local risks for port operability. This risk assessment requires that assumptions have to be made with regard to scenarios of future greenhouse gas emissions, for example the IPCC scenarios. By using these emission scenarios as input of a global climate model, global climate change predictions are obtained. Subsequently, these global climate change predictions are downscaled into regional predictions, using a regional climate model. Then, the regional predictions are downscaled into local predictions at the port location using a numerical hydraulic model or modelling suite, such as SWAN (Simulating WAves Nearshore) and Delft3D. Extreme value analysis of the downscaled local modeling results is used to translate the predicted changes in hydraulic conditions into port operability risks, expressed in terms of an increase in port downtime. Next, the relevance of the identified risks is assessed and prioritized by port stakeholders.
The final step involves exploring adaptation measures for the identified risks using a panel of experts from practical and academic backgrounds. This is undertaken in a workshop, consisting of a divergent brainstorm session in predefined categories: (1) operational: logistic and technological solutions, (2) institutional: economic, legislative and political options, (3) social: options in which the influence on the behavior of actors is considered, (4) grey: physical engineering solutions within the port area and (5) green: win-win solutions which are also benefitting the natural environment. In the subsequent convergent phase of the workshop, promising alternatives are selected by means of voting and a panel discussion.
Application to the Port of IJmuiden
The system analysis identified the following operations and physical assets as relevant to the climate change risk assessment: (1) navigational activities of vessels shipping from and towards the North Sea and the locks of IJmuiden (2) operations on quay walls and (3) berthing and mooring of vessels at quay walls in the port basins. The risk assessment revealed that regional climate change predictions for the North Sea imply the following for port downtime without adaptation measures:
- Navigational delay. The yearly averaged downtime due to high waves will be doubled from 5 to 10 days in the high emission scenario. In the moderate emission scenario, the yearly averaged downtime will rise from 5 to 7 days.
- Flooding of quay walls. Frequencies of flooding of quay walls in the port basins are expected to increase from once every few hundred years up to once every few years in the moderate emission scenario, or to once per 1-2 months in the high emission scenario.
- Delay berthing and mooring. The yearly amount of days that vessels will experience berthing and mooring problems due to waves in one of the basins will be doubled from ca. 1 to 2 days in the high emission scenario. An increase of 15% is expected in the moderate emission scenario.
The risks identified are relevant since the port is operating 24 hours per day and continuity in the operations is required. Based on the expert voting and panel discussion, the following adaptation options are identified as most promising in dealing with sea level rise: (1) increasing the quay heights and (2) construction of a retention basin in combination with a drainage system for quay walls. To deal with increased downtime due to increased storminess, the following options are identified as promising: (1) a multi-purpose land reclamation offshore of the port to provide a shelter zone for high waves and (2) the application of navigable, wave-absorbing vegetation between breakwaters. Further studies on the feasibility and effectiveness of these options are still required.
Conclusion
The conceptual framework for quantifying climate change risks for port operability and subsequently for exploring adaptation strategies was successfully applied to the Port of IJmuiden. The results of this study show that, without adaptation measures, climate change holds significant risks for port operability in the Port of IJmuiden. However, climate change impacts on hydraulic conditions are projected to be more extreme elsewhere, for example wave heights are projected to increase more rapidly due to climate change at the German and Norwegian border of the North Sea, in southern Australia, Africa, South-America and the Caribbean. This implies that climate change risks for port operability may be even larger for seaports located in these areas, and calls for attention on this issue worldwide.