Quanti-Adapt – Quantifying the needs of adaptation

16 November 2021


Multiple studies demonstrate the value of anticipating and adapting to the effects of climate change (Global Commission on Adaptation 2019; COACCH 2018). Yet the argument that the costs of inaction far outweigh the costs of action is not enough to trigger the latter (I4CE and Ramboll 2021). Indeed, global assessments provide little information on the distribution of the costs and benefits of adaptation between actors and over time.


In France, the Senate’s delegation for foresight described in 2019 a situation of “vagueness about the level of needs” for financing climate change adaptation. And indeed, in the absence of sufficiently clear and consolidated information to establish a dedicated financing plan, it remains very difficult to advance discussions and commitments to mobilize the human and financial resources necessary to properly integrate this concern into spatial planning and economic development projects.


Nevertheless, there are some fragmented cost information. Experiments have been undertaken and partially documented in different sectors and regions.




The objective of this project is to carry out a consolidation of these available cost items and to estimate the missing information on the basis of relevant knowledge and experiences. The aim is to structure an “observatory of all adaptation costs” on which to base the costs of different adaptation trajectories and thus objectify the financing needs associated with adaptation roadmaps or strategies, for example regional and sub-regional ones.


This observatory would provide quantitative information (what amounts need to be mobilized) and qualitative information (for what types of expenses, over what time frame, by what types of actors, etc.). It could become a tool that could be appropriated by a wide range of subnational actors to organize their own commitment on the one hand – particularly during programming and budgetary debates – and in their discussions and negotiations with their partners – particularly national partners – on the other.


This observatory would integrate investment needs as well as upstream needs in order to establish an enabling environment for adaptation. To achieve this, the proposed approach consists of consolidating all the existing experience and then putting it into perspective with the recommendations in the literature and the sectoral roadmaps in order to formulate hypotheses for generalization on the scale of the total French needs. The aim is to work by elementary cost bricks – each brick corresponding to a type of adaptation actions or a coherent set of actions – and to propose a formal approach for composing and articulating these bricks in order to calculate the cost of different adaptation pathways.




October 2021 – March 2023




Project conducted with the support of The French Agency for Ecological Transition (ADEME) in the framework of the PACT2e call for projects.