Objectives and needs
Given the prospect of a temperature rise that could exceed +4°C, and lower levels of summer rainfall in France by 2100, some parts of the country could be more severely and more frequently affected by summer droughts before the end of the 21st century. This will mean less water available from rivers and a lower level of groundwater. Water is a common good that is essential in many areas: economic activities (farming, industry, tourism), drinking water for local communities, and the preservation of aquatic environments. The scarcity of this natural resource could lead to conflicts that must be addressed ahead of time.
The Explore2 project, led by the Institut de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE) and supported by the International Office for Water (IOWater), follows on from the Explore 2070 study (2010-2012) carried out by the Ministry of Ecological Transition. This new project was officially launched in July 2021.
Financed by the Ministry of Ecological Transition and the French Office for Biodiversity, Explore2 is scheduled to run until 2024. Its purpose is to update knowledge of the impact of climate change on hydrology based on the latest IPCC publications, but also to support regional stakeholders in understanding and applying these results to adapt their resource management strategies.
Explore2 is based on a scientific consortium led by INRAE and bringing together a range of research players (Météo-France, BRGM, ENS-PSL, Sorbonne University, IRD, CNRS and EDF). The scientific strand of the project will seek to assess the impact of climate change on water resources during the 21st century and in Metropolitan France. These data (time series and hydrological indicators) will be based on contrasting greenhouse gas emission scenarios and a set of climate models and hydrological models. This will make it possible to estimate uncertainties, applying a common methodology to all regions.
The second strand of the Explore2 project, coordinated by IOWater, will seek to develop a dialogue with users of the results (basin committees, water boards, local authorities, consultancies). This will enable regional entities to initiate forward-looking approaches on water uses and the conditions for sustainable management, and to implement appropriate measures for adaptation. In this way, these new hydroclimatic forecasts will be very useful for reviewing the master plans for water development and management scheduled to begin in 2025, as well as for preparing the 100 "regional projects for water management" for 2027, reviewing the regional climate air and energy plans in 2023, and developing flood prevention action programmes.
All the results will be made available on a hydroclimatic services portal dedicated to water, based on the same model as the current DRIAS "Climate futures" portal, which provides regionalised climate information for France. The first version of this "DRIAS-Water" extension was created as part of the LIFE Eau&Climat project and became operational in early 2022, with the final version being scheduled for 2024.
BRGM is a partner in the "groundwater hydrology" strand of the project. Using the AquiFR hydrogeological modelling platform, the North-Aquitaine hydrogeological model (MONA), and the EROS Loire and EROS Brittany distributed models, will make it possible to simulate changes to future water table levels and to characterise the extremes over the entire 21st century for different greenhouse gas emission scenarios (RCP2.6, RCP4.5 and RCP8.5), against the backdrop of climate change. Changes to future recharging will also be characterised using the potential recharge estimation method based on the calculation of the IDPR (network development and persistence) index developed at BRGM. All simulated and estimated data will be made available on the DRIAS-Water portal at the end of the project.
- Ecole Normale Supérieure-PSL
Method for estimating recharges across France: Sandra Lanini, Yvan Caballero, Pierre Le Cointe, Sandra Béranger, Luc Arnaud, et al. Evaluating future groundwater recharge with associated uncertainty at the scale of France. SHF-UNESCO Conference: Droughts, low flows and water scarcity, Dec 2019, Paris, France.