Establish baseline conditions and understanding of future changes (in climate-related parameters)

For ports, a critical step in climate change adaptation and resilience planning is developing a sound understanding of baseline conditions, likely future climate changes, and the associated uncertainties. This includes Climate risk screening, climate data collection, identifying uncertainties.

Because ports are long-lived assets operating in dynamic coastal environments, adaptation planning must account for both gradual changes and extreme events, while remaining robust under uncertain future conditions.

Adaptation planning requires building an evidence base that identifies relevant climate drivers, establishes baseline conditions, and assesses how these may change under different climate scenarios before progressing to detailed risk assessment. Climate data selection must reflect asset sensitivity, planning horizon, decision context and available expertise, recognizing that data vary across spatial and temporal scales.

Relevant climate parameters are identified by linking potential impacts to drivers such as sea-level rise, rainfall, winds, waves, river flows, temperature extremes and sediment processes. Historical data support trend and threshold analysis, while scenario-based assessments help explore conditions beyond past experience. Given growing uncertainty, particularly for complex processes such as sea-level rise and waves, using multiple scenarios, models and adaptive decision-making approaches is essential for resilient port planning.

For ports, it is an essential step in the climate change adaptation and resilience process to develop a comprehensive understanding of baselines conditions and likely future changes, in both drivers of change and impacts. Further, given the uncertainty surrounding climate change, understanding uncertainty in climate change projections and being adaptative to such uncertainty is critical.

Ports are particularly exposed to various climatic hazards, due to their locations along open coasts or in low-lying estuaries and deltas that make them susceptible to the impacts of rising sea levels, storm surges, waves and winds as well as fluvial and pluvial flooding (Izaguirre et al. 2021). Without effective adaptation, these risks are projected to intensify under climate change (Izaguirre et al. 2021).

The climate change adaptation planning process requires the development of an evidence base to understand how future climate change may affect critical maritime and inland navigation assets, operations and systems. The objective is to identify relevant climate parameters and processes, establish baseline conditions, and assess how these may change under different climate change scenarios, before progressing to risk assessment (PIANC 2020).

The process begins by establishing climate information needs, recognizing that climate data vary widely in spatial and temporal scale, from global to site-specific and from long-term averages to extreme events. Decisions on data requirements depend on asset location, susceptibility to hazards, planning horizon, adaptation objectives, and available technical expertise. Establishing robust baseline conditions is essential, as these form the reference point for assessing future change.

Relevant climate parameters and processes are identified by linking known or potential impacts to climate drivers such as sea level rise, precipitation, winds, waves, river flows, temperature extremes, sediment transport and visibility. While historical impacts provide important insight, additional parameters should also be considered through scenario-based “what-if” analyses, recognizing that future conditions may exceed past experience. Stakeholder engagement is critical at this stage, drawing on operational knowledge to ensure all relevant vulnerabilities are captured.

Collation of baseline climate data, including long-term records of average conditions and extreme events concerning the above supports trend analysis, threshold identification, and comparison with future projections. Where data gaps exist, local monitoring may need to be initiated.

Future climate conditions are explored using climate change scenarios, most commonly IPCC Representative Concentration Pathways (RCPs) and, since the IPCC Sixth Assessment Report, Shared Socioeconomic Pathways (SSPs). The number of scenarios considered should align with the adaptation planning horizon, with greater emphasis on multiple scenarios and uncertainty for long-term planning beyond mid-century. Changes in the frequency and severity of extreme events must be explicitly considered, as these pose significant risks to infrastructure and operations.

Baseline and projected data are analyzed using methods appropriate to data quality and decision needs, with explicit recognition of uncertainty and data limitations.

Understanding uncertainty in climate change projections is essential. The IPCC (Mastrandrea et al., 2010) has developed a consistent framework and terminology to describe uncertainty in climate change projections, distinguishing between confidence in scientific understanding and the likelihood of specific outcomes. Uncertainty increases as projections move from well-understood variables like temperature to more complex processes such as sea level rise, waves, sediment transport and ecosystem impacts, all of which are significant for ports.

-Regional projections vary significantly between scenarios, reflecting uncertainties in future emissions, climate system responses and internal variability. Using multiple models and scenarios is therefore essential. For navigation and port planning, emphasis should be placed on understanding trends and managing uncertainty through scenario selection, sensitivity testing and adaptive, resilient decision-making (PIANC, 2023).