Climate change data
Against a backdrop of increasing climate change, the Provence-Alpes-Côte d’Azur region is one of the areas most exposed to natural hazards in France. Flooding, marine submersion, heat waves, landslides and drought are all increasing threats to infrastructure and mobility. To better anticipate these risks and adapt its transport system for 2050, the region has launched an in-depth study. The aim is to carry out a multi-network vulnerability diagnosis of its transport infrastructure.Context and challenges
This study is part of the regional climate plan ‘Une COP d’avance II’. The plan aims to set an example on a national scale. It is an integral part of our climate change data service.
The aim of this vulnerability diagnosis is to provide a sound scientific and operational basis for adaptation planning. It is based on the ASAIT (Approche Systémique d’Adaptation des Infrastructures de Transport) methodology developed by Cerema. This methodology enables a detailed vulnerability diagnosis of the physical and functional vulnerabilities linked to climate hazards, in relation to climate change scenarios.
This vulnerability diagnosis is divided into 3 major stages. The first phase will involve scoping and governance, with the aim of collecting data. The second phase will involve carrying out a physical and functional vulnerability diagnosos. The aim of this vulnerability diagnosis is to provide a solid scientific and operational basis for adaptation planning.
The first phase of the vulnerability diagnosis laid the technical, methodological and partnership foundations for the project. It began with a strategic framing exercise conducted with regional departments, infrastructure managers (SNCF Réseau, DIRM Méditerranée, DIR Méditerranée, VNF, airport managers) and government departments.
The study perimeters have been refined to cover the major transport networks structuring the region:
Alongside the strategic framework, a typology of relevant climatic hazards has been drawn up. It includes the following indicators:
A wide variety of sources were used to collect the data: infrastructure inventories, technical databases, local diagnoses and, above all, climate projections based on the Drias, Explore2 and CMIP6 models. This wealth of information has been structured into a common reference system, enabling the foundations to be laid for future vulnerability diagnostics: clay shrinkage and swelling.
A major awareness-raising campaign was also carried out among the technical and institutional players. The aim was to involve them in the cooperative governance of the study. This mobilisation is essential to ensure the continuity of the action beyond the diagnostic phase.
The second phase of the vulnerability diagnosis is based on Cerema’s ASAIT methodology. This cross-referencing of data is designed to produce a map of the risk on a regional scale. The aim of this cross-referencing of data is to produce a map of the risk on a regional scale.
The diagnosis distinguishes between two types of vulnerability:
Each piece of infrastructure is modelled in terms of its technical components (pavements, engineering structures, catenaries, rights of way, equipment), which are then analysed in terms of :
By cross-referencing these dimensions, we can produce a level of climate risk for each section or infrastructure node. This scoring is then aggregated to identify the priority areas requiring rapid adaptation.
This vulnerability diagnosis revealed critical points on all the networks:
The result is a mapped, well-argued vision of future climate risks. This is a powerful decision-making tool for planning purposes.
On the basis of the vulnerability diagnosis, an adaptation roadmap was drawn up jointly with infrastructure managers, mobility organising authorities and decentralised government departments.
This adaptation strategy has several components:
The partnership approach was strengthened at this stage by the organisation of multi-stakeholder workshops. This approach enables local priorities to be compared with the results of the technical diagnosis. This collaborative approach ensures greater ownership of the issues and greater operational efficiency.
This study is the first of its kind in the Provence-Alpes-Côte d’Azur region. Expected results and outlook:
It paves the way for the implementation of a multi-scale adaptation plan. It will help to secure infrastructures and guarantee the resilience of regional mobility. Ultimately, the approach is intended to be replicated in other French regions facing similar hazards.
The vulnerability diagnosis carried out on transport infrastructures in the Provence-Alpes-Côte d’Azur region is a key step. It is becoming a key element in anticipating the effects of climate change and guiding adaptation policies. Thanks to a rigorous methodology, a broad-based partnership and up-to-date climate data, this approach makes it possible to identify the network’s critical points and to build a coherent, prioritised and operational adaptation strategy.
This work is more than just a snapshot of what already exists. It provides concrete levers for strengthening the resilience of regional mobility, ensuring the continuity of public services in a climate crisis and securing long-term investments. It also marks a turning point in the way in which local and regional authorities can take a systemic approach to the climate transition.
This vulnerability diagnosis positions the southern region as a pilot area for climate transition in the transport sector. This is due to an integrated, scientific and territorial approach to risks and solutions.
