Chapitre 1. Les stocks de carbone des sols d’Afrique de l’Ouest

Introduction Les sols jouent un rôle primordial dans notre environnement de par leur capacité d’échange d’éléments nutritifs et de régulation. Le changement climatique est aujourd’hui la crise environnementale la plus importante et les sols y jouent un rôle prépondérant, essentiellement de régulation via le cycle du carbone. Le dioxyde de carbone (CO2) est, de loin, le plus grand contributeur d’origine anthropique à l’effet de serre et au changement climatique. De plus, environ les deux tiers..

Méthodologie De Production Des Données Cartographiques Sur Le Couvert Forestier En République Du Congo, De 2000 À 2012

A forest-based mapping data production study was conducted in the Republic of Congo as part of the Reducing Emissions from Deforestation and Forest Degradation (REDD) process including sustainable forest management, forest conservation, and forest degradation. biodiversity and increasing carbon stocks (REDD +). The purpose of this study was to produce a forest cover map and cover changes for the period 2000 to 2012, which meets the criteria of the national definition of forest adopted by the Republic of Congo and the evaluation of forest areas. and losses. The map produced was based on the combination of forest map parameters developed prior to the adoption of the forest definition criteria. The 2000 and 2010 Landsat image segmentation was used to create polygons that respect the definition and in which the values of the underlying maps were injected, through a decision tree transcribed in the R language and implemented in conjunction with the tools Open Foris Tools Kit. The results indicate an overall accuracy of 90% of the map without stratification, with greater accuracy for the forest (86%) than for the losses (73%). The forest occupies 23,517,000 hectares, representing 69% of the national territory. The forest area lost during this period was estimated at about 145,356 hectares, which represents an annual average of 12,113 hectares (0.052%). These results lead to the conclusion that the Republic of Congo is one of the countries with high forest cover and low deforestation

Carbone des sols en Afrique

Les sols sont une ressource essentielle à préserver pour la production d’aliments, de fibres, de biomasse, pour la filtration de l’eau, la préservation de la biodiversité et le stockage du carbone. En tant que réservoirs de carbone, les sols sont par ailleurs appelés à jouer un rôle primordial dans la lutte contre l’augmentation de la concentration de gaz à effet de serre. Ils sont ainsi au centre des objectifs de développement durable (ODD) des Nations unies, notamment les ODD 2 « Faim zéro », 13 « Lutte contre le changement climatique », 15 « Vie terrestre », 12 « Consommation et production responsables » ou encore 1 « Pas de pauvreté ». Cet ouvrage présente un état des lieux des sols africains dans toute leur diversité, mais au-delà, il documente les capacités de stockage de carbone selon les types de sols et leurs usages en Afrique. Il propose également des recommandations autour de l’acquisition et de l’interprétation des données, ainsi que des options pour préserver, voire augmenter les stocks de carbone dans les sols. Tous les chercheurs et acteurs du développement impliqués dans les recherches sur le rôle du carbone des sols sont concernés par cette synthèse collective. Fruit d’une collaboration entre chercheurs africains et européens, ce livre insiste sur la nécessité de prendre en compte la grande variété des contextes agricoles et forestiers africains pour améliorer nos connaissances sur les capacités de stockage de carbone des sols et lutter contre le changement climatique

Assessing Global Forest Land-Use Change by Object-Based Image Analysis

Consistent estimates of forest land-use and change over time are important for understanding and managing human activities on the Earth’s surface, parameterizing models used for global and regional climate change analyses and a critical component of reporting requirements faced by countries as part of the international effort to Reduce Emissions from Deforestation and Degradation (REDD). In this study, object-based image analysis methods were applied to a global sample of Landsat imagery from years 1990, 2000 and 2005 to produce a land cover classification suitable for expert human review, revision and translation into forest and non-forest land use classes. We describe and analyse here the derivation and application of an automated, multi-date image segmentation, neural network classification method and independent, automated change detection procedure to all sample sites. The automated results were compared against expert human interpretation and found to have an overall agreement of ~76% for a 5-class land cover classification and ~88% agreement for change/no-change assessment. The establishment of a 5 ha minimum mapping unit affected the ability of the segmentation methods to detect small or irregularly-shaped land cover change and, combined with aggregation rules that favour forest, added bias to the automated results. However, the OBIA methods provided an efficient means of processing over 11,000 sample sites, 33,000 Landsat 20 × 20 km sample tiles and more than 6.5 million individual polygons over three epochs and adequately facilitated human expert review, revision and conversion to a global forest land-use product

The Importance of High–Quality Data for REDD+ Monitoring and Reporting

This article discusses the importance of quality deforestation area estimates for reliable and credible REDD+ monitoring and reporting. It discusses how countries can make use of global spatial tree cover change assessments, but how considerable additional efforts are required to translate these into national deforestation estimates. The article illustrates the relevance of countries’ continued efforts on improving data quality for REDD+ monitoring by looking at Mexico, Cambodia, and Ghana. The experience in these countries show differences between deforestation areas assessed directly from maps and improved sample-based deforestation area estimates, highlighting significant changes in both magnitude and trend of assessed deforestation from both methods. Forests play an important role in achieving the goals of the Paris Agreement, and therefore the ability of countries to accurately measure greenhouse gases from forests is critical. Continued efforts by countries are needed to produce credible and reliable data. Supporting countries to continually increase the quality of deforestation area estimates will also support more efficient allocation of finance that rewards REDD+ results-based payments

Small scale agriculture continues to drive deforestation and degradation in fragmented forests in the Congo Basin (2015–2020)

International audienc

Restoring Degraded Landscapes through an Integrated Approach Using Geospatial Technologies in the Context of the Humanitarian Crisis in Cox’s Bazar, Bangladesh

The influx of nearly a million refugees from Myanmar’s Rakhine state to Cox’s Bazar, Bangladesh, in August 2017 put significant pressure on the regional landscape leading to land degradation due to biomass removal to provide shelter and fuel energy and posed critical challenges for both host and displaced population. This article emphasizes geospatial applications at different stages of addressing land degradation in Cox’s Bazar. A wide range of data and methods were used to delineate land tenure, estimate wood fuel demand and supply, assess land degradation, evaluate land restoration suitability, and monitor restoration activities. The quantitative and spatially explicit information from these geospatial assessments integrated with the technical guidelines for sustainable land management and an adaptive management strategy was critical in enabling a collaborative, multi-disciplinary and evidence-based approach to successfully restoring degraded landscapes in a displacement setting