La Rochelle Zero Carbon Territory - Blue carbon roadmap (LRTZC)
Urban Community of La Rochelle – France
Dates : 2019-2026
Project leader: University of La Rochelle, Urban Community of La Rochelle, City of La Rochelle
Classification
Risks
Solutions
Actors
Costs
Summary
The La Rochelle Zero Carbon Territory (LRTZC) project addresses mitigation and adaptation to climate change issues. The “blue carbon” axis promotes wetlands’ and coastal ecosystems’ capacities to sequester carbon. The project is divided into 4 complementary actions, each combined with scientific research :
- Action 1: Assess and monitor carbon capture by the coastline and marshes along the ocean/intertidal swamp/hinterland continuum.
- Action 2: Protect coasts against floods and erosion.
- Action 3: Develop decision-making tools for coastal zone and marshes managers.
- Action 4: Assist local stakeholders in the transition, and replicate the actions accross the national territory.
While only Action 2 is specific to coastal protection against climate change impacts, all actions are connected to this issue as wetlands are critical ecosystems for climate change adaption and mitigation through their carbon sequestration services. Given that the “Blue Carbon” approach aims at optimised management and better preservation of these environments, all the actions contribute to the adaptation of the territory to sea level rise.
Actions
Action 2 plans for the implementation of “hard” and “soft” protection responses. Given the impacts of climate change and sea level rise, the objective is to implement innovative strategies for coastal protection. This action aims to improve the understanding and prediction of the hydro-sedimentary dynamics and long-term evolution of foreshore and natural barriers to propose tailored adaptation solutions to climate change.
The added value of “soft” coastal protection, such as the preservation or development of seagrass beds at the top of the foreshore and the creation of buffer zones will be quantified. Finally, coastal defences will be reinforced by an experimental technique favouring calco-magnesian deposits. More generally, the study of carbon flows in wetlands and coastal areas should improve the management and preservation of these areas, which are essential for the adaptation of territories to rising sea levels.
Actions 3 and 4 focus on capacity-building and knowledge sharing activities.
First of all, the Actions’ results will be used and put forward to produce maps and tools modelling the ecosystems evolution and propose steering and management support to local actors for the shoreline and marshes. In turn, it will enable the emergence of integrated management strategies that optimise carbon sequestration services.
Finally, only the mobilisation of all the stakeholders and managers of coastal areas and marshes can make possible the initiation and support of impactful changes in the region. Work will be carried out to identify and evaluate governance methods, as well as raise awareness on the notion of blue carbon among the general public. The second phase aims to replicate the experience to other territories at the departmental, national and international levels.
Action 1 plans for an in-depth study of carbon flows within the ecosystems, which is necessary to maximise carbon sequestration capacities of coastal and wetland environments. The studies carried out on carbon flows aim to improve knowledge on :
- Atmospheric CO2 exchanges on the coastline, marshes and the terrestrial zone of the La Rochelle Agglomeration;
- Terrestrial export and tidal advection of carbon along the land-sea continuum, and in particular the impact of dredging/sediment removal at sea and sediment cleaning in marshes on the carbon balance;
- Benthic flows on mudflats and at sea;
- The dynamics of carbon processes and stocks within the benthic and pelagic levels;
- Carbon stock dynamics in sedimentary and soil cells
These studies can guide and evaluate the operations carried out under Action 2 by improving knowledge on:
- Hydro-sedimentary dynamics and the evolution of foreshore and natural barriers;
- Quantification of the added value of innovative coastal defence strategies (seagrass beds/buffer zones)
- The effectiveness of a mechanism to reinforce coastal defences via a process favouring calco-magnesian deposits
Outcomes
The project is ongoing, the results are not yet known.
The close collaboration between the University, the Agglomeration, the City and other partnerships (Geocorail company) established with NGOs is central for the project continuation.
In addition, the Blue carbon approach and other levels of the LRTZC project are strongly intertwined, in particular the “Citizen participation” front, which will allow citizen involvement and awareness of the issues associated with blue carbon and coastal adaptation to climate change. The “DATA” front will be used to develop modelling and decision support tools.
As an innovative project, knowledge gaps on a global scale remain while predictions on the results of this initiative are still uncertain.
Similarly, the concepts studied are still poorly understood by local stakeholders, who have a direct impact on wetlands and coastal areas through their management methods and decisions. Therefore, it will be critical to focus on awareness-raising and training to make these issues more accessible to the largest and thus succeed in involving as many people as possible.
Partners
Technical partners: University of La Rochelle, City of La Rochelle, Urban Community of La Rochelle, associations, corporations
Financial partners: “Programme d’Investissements d’Avenir”” (PIA), ADEME, Region of Nouvelle-Aquitaine, Ports, Cities, CDA