Economic implications of adaptation pathways

6 July 2023

The French Inspection générale de l’environnement et du développement durable (General inspectorate for environment and sustainable development) notes in the report by its Mission de Parangonnage sur les Politiques d’Adaptation au Changement Climatique (Mission on benchmarking for climate adaptation policies) (2023) that resource mobilisation for adaptation is not yet based on exhaustive assessments of the cost of adaptation. Taking the elements already put forward by the MPs Ronan Dantec and Jean-Yves Roux in the report by the French Senate’s Délégation à la Prospective (Delegation for strategic foresight) (2019), the authors explain that this is due partly to the large number of actors concerned and to the relatively diffuse nature of the costs, and partly to the fact that it is often difficult to distinguish adaptation costs in the calculation from existing policies to improve resilience, which pursue different objectives.


Various studies conducted in recent years nevertheless constitute a solid working foundation on which to build initial needs assessments:

  • estimates of the cost of inaction, in other words the cost of the damage that will be caused by climate change if nothing is done to prepare for it;
  • first elements to quantify the resources needed for adaptation, in particular taken from the Quanti-Adapt project.


Such an assessment appears increasingly necessary in the context of the growing importance of adaptation in public policies, and especially of preparations for the 3rd French National Adaptation Plan (PNACC3), expected for late 2023.


The first bricks of this plan were laid with the launch in spring by the French Minister for Ecological Transition and Territorial Cohesion of a public consultation on the implementation of a reference warming trajectory for adaptation to climate change in France (TRACC).


Objectives :

In this context, the goal of this project is to contribute to the French public debate insights on the economic implications of different adaptation scenarios corresponding to the warming levels considered in this trajectory.


It will focus particularly on clarifying the state of knowledge on public financing needs for adaptation in three priority sectors: building, transport infrastructure and agriculture.


For each of these sectors, the goal will be to:

  • determine the best way to think about the economic consequences of the different warming trajectories;
  • consolidate the quantitative and qualitative elements that are available or can be produced on these economic consequences according to different warming levels;
  • initiate a discussion on these elements with key stakeholders.


There cannot be a single adaptation cost per warming scenario: in fact, the cost of adaptation depends not only on the level of impact for which to prepare, but also on the level and type of preparation implemented. Placing the cursor between the cost of impacts (i.e. of inaction) and the cost of adaptation (i.e. of anticipation) therefore implies collective choices that mostly still need to be made. The findings of this study are thus intended to open and inform discussions on the options available, rather than to choose between them.


Technical partners:

To conduct this project, I4CE works with Observatoire de l’Immobilier Durable (Sustainable property observatory, OID, on the building sector), FINRES (on the agricultural sector), SETEC and Callendar (on the transport sector). The expertise of a wide range of sectoral partners will also be mobilised throughout the research project in different forms (expert committees, targeted contributions, etc.).


Financial partners:

Project conducted with the support of the Bureau de l’Adaptation au Changement Climatique du Ministère de la transition écologique (ex ONERC), ADEME and CGDD.



Support by

Mars 2023 – Janvier 2024
I4CE Contacts
Senior Research Fellow – Adaptation and Local authorities Email
Guillaume DOLQUES
Guillaume DOLQUES
Research Fellow – Climate Change Adaptation Email
Morgane NICOL
Morgane NICOL
Local authorities Programme director – Local authorities, Adaptation, Public finance Email