ECLAT: Climate Change in the Lac Chad Region

Published on 06/08/2021
There are places on Earth where anthropic and climatic pressures are intertwined with human conflicts. Faced with such a complex situation, the ECLAT project is experimenting with a powerful methodology in the Lake Chad region. After a year of meetings, exchanges and maturation, the project has been refined and has begun the first technical work in spring 2021.

Between climate change and human conflicts, ECLAT is not a project like any other. What is its genesis?

Christophe Sannier, Head of the International Research and Development Unit at CLS: It all started with an ESA project, EO4SD FCS (Fragility, Conflict and Security), dedicated to fragile states experiencing situations of violence. Within this framework, my colleagues and I came into contact with the World Bank and, through it, a program around the Lake Chad basin.

The more or less natural evolution of the lake's extent is putting significant pressure on water resources and the environment in one of the poorest regions in the world. Land degradation, coupled with conflict situations and the impacts of climate change, create a very complex and difficult situation to understand. Especially since these areas, despite their desert appearance, have one of the highest population growth rates in the world, with de facto risks in terms of food security.

We then met with people from the UNDP and then from the GMES Africa program. Enthusiastic, they showed interest in the project by extending it to the region in order to have a wider involvement of stakeholders. We then exchanged with the African Union, noting the "alignment" of ECLAT with a project on wetlands carried out by the Ecological monitoring center (CSE, Centre de Suivi Ecologique) in Dakar. In contact with the CSE, we redefined the contours of ECLAT to meet their needs, in line with the UN's sustainable development goals.

In fact, what are the new directions of the ECLAT project?

C.S.: Keeping the same course, ECLAT focuses on a better understanding of the interactions between anthropic pressures and climate change and on the sustainability of available resources. In addition to the initial experimental area, west of Lake Chad, there is an area along the Niger River and a coastal area in Senegal where CSE is working with the African Union. ECLAT will therefore provide in an automated way 1) land use indicators, from which socio-economic indicators will be extracted, starting with the identification of residential areas, 2) a monitoring of the water resources of Lake Chad and 3) a monitoring of wetlands.

Suivi occupation des sols

Monitoring inhabited areas and land use around Lake Chad. © ECoLaSS/Background : OpenStreetMap contributors

What is the technical objective?

Santiago Pena Luque, project manager at CNES: Since ECLAT is intended to provide automated decision support tools based on space imagery, the primary objective is to provide a transposable methodological framework that will allow us to know where to calculate indicators in a reliable and sustainable manner. We focus more on natural than urban environments and on interactions with refugee camps, which can have a significant impact on the environment. We also focus on providing the CSE with information on wetlands, an environment with complex dynamics but which long satellite time series allow for in-depth study.

What is this methodology and why is it powerful?

S.PL. (CNES): Everything starts with a large amount of upstream reference data. CLS brings to this project a remarkable expertise in the validation of these reference maps that will allow the generation of good quality indicators. The Iota 2 processing chain (developed by CNES) can then absorb all the time series of satellite data to enrich the existing data, especially during periods when there is little data. It can then calculate land use indicators that can be compared with other sources, such as water stress, refugees, etc.

C.S. (CLS): We have indeed carried out an inventory of available data - very high resolution satellite data, mainly from the Copernicus program, aerial photos, etc. - whose use can be maximized. Our thematic experts have evaluated several classes of data and determined which ones describe the environment with the best reliability of details. Therefore, our approach is to decouple the three types of changes: abrupt, cyclic and long-term, the latter being attributable to climate change. We will thus be able to see first the nature of anthropogenic pressures, then to observe changes in the soil (humidity, evolution towards agricultural land, etc.) and finally to deliver indicators of more or less long-term evolution of the natural environments (increase or reduction of net primary production, water surface, etc.).

What does this have to do with conflict?

C.S.: Let's take the preliminary study conducted on a refugee camp in northern Cameroon. Time series over several years show a significant decrease in the surrounding resources, especially in the vegetation index. Correlated with the camp, it appears that this decline is due to the collection of firewood by the refugees. However, if this pressure on resources intensifies to the point where wood becomes unavailable, it may itself become a source of conflict, with resonance on a geopolitical scale. ECLAT can therefore, for this example alone, lead to concrete solutions - such as putting in place accompanying measures to provide refugees with alternative means of cooking - and avoid further conflicts. The tool can even track the impact of investments made to stabilize populations.

Carte changements camp de réfugiés Cameroun

Monitoring map of land use changes around the Minawao refugee camp in Cameroon.

In your opinion, what added value does the SCO labeling bring to the project?

S.PL. The SCO label provides a good framework for validating the operational prototype of this methodology. It allowed us to prepare all the analysis work upstream, and in particular to identify all the input data to guarantee the quality of the indicators delivered. The second strength of the SCO for this project is its transposability.

C. S.: I would add that the fact that CNES is associated with the SCO label has facilitated, if not allowed, contacts with the African Union and the SSC, meetings that are essential to gain the necessary maturity for such a project.

What are the next steps?

C.S.: We are now working on identifying the data that we could combine "intelligently". We are also continuing the analysis of time series to create, thanks to the Iota 2 processing chain, the data that are missing for certain periods. Finally, we are refining the calculation of indicators on the study sites. All this while thinking about the next steps, taking advantage of the SCO to find new partners and funding in order to evolve on larger scales.