À partir de trames vertes et bleues (TVB) parisiennes délimitées par des inventaires floristiques et des travaux géomatiques, l’étude a cherché à comprendre les usages et représentations de ces espaces. Dans cette matrice densément peuplée (20 807 habitants par km²) et bâtie (41 %), peu étendue (105 km²), les Parisiens conçoivent ces espaces comme des lieux de respiration et de liberté. Leurs représentations sont davantage liées à leurs pratiques qu’à leurs catégories sociales. Les variables de genre, d’âge ou de niveau scolaire n’interviennent sur les représentations que si elles influencent l’usage des habitants. Deux visions des TVB se dessinent, l’une reconnaissant le lien fort entre l’homme et la nature et l’autre postulant leurs différences. Pour la première, les TVB doivent être défendues en ville parce qu’elles font partie du quotidien des habitants et pour l’autre elles n’ont pas leur place dans une métropole comme Paris. Ces résultats peuvent être utiles à l’heure de la mise en place de la politique des trames vertes et bleues à Paris.

This paper contributes to a critical re-reading of the notion of climate services. It does so by problematizing the discontinuity between young people’s commitment to climate change, and the lack of a common vision regarding climate policy among governments. In this essay, youth commitment is characterized in terms of participation in the Global Youth Climate Pact (GYCP, 2015–2022). Here, young people share projects from their own high schools and communities and participate in a citizen consultation. Most projects have achieved a good success score, increasing over the years, especially for those carried out in emerging and developing countries. Some of them were presented at the COPs. In contrast, a textual analysis of intended nationally determined contributions (INDC) illustrates divergent understandings of the Paris Agreement and exemplifies the poor results of governmental climate diplomacy. This study establishes the need to closely monitor early warning signs of climate change in conjunction with high schools and school communities. The initiatives of young people are building a civic and planetary awareness for climate change in contrast with governmental division and inertia. In this sense, climate services, directed to young people, could contribute to design a sustainable future. We approach the practices, attitudes, and commitments of young people from the angle of cooperation rather than a moral vision of responsibility. Particularly, we propose a dialogical link between the treatment of climate issues and its effects on the constitution of networks, notably as they relate to practices of action, that is, the way in which distinct groups of young people develop relationships with their environments, organize themselves, and act and transform reality.

Dans le Nordeste du Brésil, les petits agriculteurs du Sertao semi-aride sont fragilisés par des sécheresses récurrentes. Des chercheurs français et brésiliens ont mené une recherche interdisciplinaire sur les interactions entre ces sociétés rurales et leur environnement. Un double regard - celui des sciences sociales et celui des sciences de la nature - permet d'évaluer la viabilité écologique et sociale des stratégies paysannes pour la génération d'aujourd'hui et pour celles de demain. La menace de la sécheresse est appréhendée à une échelle régionale, puis locale. Deux visages du Sertao coexistent : l'un, qualifié de « traditionnel », continue à privilégier l'élevage extensif, mais se trouve confronté à une lente dégradation des pâturages de la caatinga ; l'autre, dit « moderne », fait le choix d'une agriculture irriguée et orientée vers le marché, mais bute sur la vulnérabilité des ressources en eau et des sols. Le suivi, pendant douze années, de deux groupes d'agriculteurs incarnant ces stratégies permet de comprendre et de comparer les logiques, les contradictions mais aussi les capacités d'évolution de chacun d'eux dans un contexte marqué par l'incertitude, tant climatique que socio-économique.

The Tlemcen region is characterized by very diverse and steep areas exposed to gravity hazards, especially in high and medium mountain areas. Tlemcen National Park was chosen for this study, the main objective of which is to map fragile areas in close relation to reduced vegetation cover due to land-use changes and forest fires. Multi-source data were used to monitor land use/land cover (LULC)patterns in the study area between 1987 and 2017. The methodology is based on an object-oriented classification of the Landsat images, using the K nearest neighbor method for mapping the major LULC classes at the national park level. The results show that LULC is constantly changing in the study area. In 1987, the landscape was made up of (16.5%) oak forests (holm oak, cork oak, zean oak) and Aleppo pine, which then deteriorated following repeated fires in the nineties to barely represent 7.22% of the surface in 1995, followed by a fast forest reclamation, with the forest area doubling in 10 years (13.46% of the area in 2005), and a near stabilization of the forest cover in 2017 with 14.68% of the area. These mutations are mainly due to fluctuations in anthropogenic action. Despite past declines and disturbances, the current forested area in the Tlemcen area represents significant forest capital classified as a national park to be protected and developed.

<!--BeginNoIndex--> Premières lignes <!--EndNoIndex--> Le paysage peut-il devenir un élément majeur des politiques urbaines ? Tel est l’enjeu des travaux de recherche que nous avons menés à Paris dans trois îlots à la morphologie et aux composantes sociales différenciées. Ces travaux concernant un petit nombre d’enquêtes, de mesures et de lieux se veulent plutôt exploratoires (encadré 2.1). Notre démarche itérative ne constitue pas l’analyse d’un socio-système ;...

Terraced historical landscapes have multiple functions in mountain land, limiting erosion, enabling agricultural production and constituting cultural heritage. Currently, they are largely abandoned in Mediterranean regions and facing the ongoing impacts of climate change. Our aim is to reconstruct the evolution of land use on the terraces in order to test the hypothesis of the resilience of these landscapes and their age in recent history (17th–21st century). To achieve this, we used various current and archive spatial datasets and GIS knowledge to detect and map terraces and the changes in land use. We tested this hypothesis in a territory impacted by a recent extreme event, facing the challenge of its reconstruction. Our main outcome showed that the optimal use of the terraces corresponded to the demographic optimum of the mid-19th century, and they were gradually abandoned after the Second World War, with significant differences between Mediterranean and mountain lands. Despite this evolution, the terraces persisted and withstood an extreme event, validating our resilience hypothesis and opening avenues for the revitalization of this territory based on this heritage. These findings are drawing perspectives for the future of terraced landscapes in Mediterranean mountains in the context of climate change.