Tropical semi-arid regions expanding over temperate latitudes under climate change

International audienc

Building a typology of cropping practices from comparison with a technical reference: first step for a relevant cropping system redesigning process – results for tropical citrus production

Introduction. Farm typologies and cropping practice typologies generally aim at seeking determinants of existing crop management strategies. They constitute the first step for setting improvement goals for cropping systems. Though there are a host of farm typology methods, few deal specifically with farmers’ practices, and even fewer investigate the correlations between practices. We propose here a framework for analysing the determinants of crop management, based on a vision of a crop management sequence condensed into logical combinations of cropping techniques. Materials and methods. This analytical framework was applied to the case of Guadeloupian citrus production, using a representative sample of 41 producers. Three stages were necessary to implement our analytical framework. At stage 1, logical and ordered combinations of cropping practices (CCPs), constitutive of observed as well as reference crop managements (RCMs), were identified through expert analysis. Based on measurements of deviations between farmers’ CCPs and RCMs’ CCPs, a typology of cropping practices was next built. At stage 2, the performances of farmers’ crop managements were evaluated using relevant indicators. Finally, at stage 3, constraints – either related to the environment or to the whole farm management – that determined producers’ cropping practices were identified for making, with the stakeholders, proposals for further technical improvements. Results. Crop management sequences were condensed into five CCPs. A technical profile was then determined for every producer, before a multiple correspondence factorial analysis was run. It identified two groups of producers with contrasting technical profiles. The collective analysis of these results pointed out “weed management” as a major constraint on the cropping systems, revealing that the RCM was inadequate in a context of impossible mechanisation. Discussion. Restructuring complex sequences of cropping techniques into five logical combinations of techniques enabled the comparison with a reference crop management. The cropping systems’ constraints and the objectives for further improvements were then set up collectively by the farmers and social stakeholders, along with the researchers. This analysis constitutes the first stage of a process of redesigning cropping systems, and its result provides a sound basis for a participatory approac

Cyclones et changement climatique : un séminaire national

International audienc

Impacts of Greenland and Antarctic Ice Sheet melt on future Köppen climate zone changes simulated by an atmospheric and oceanic general circulation model

Climate change studies in recent decades have been based on Global Climate Models (GCMs), and the changes in the distribution of climatic regions over time extracted from these models can be represented using the Köppen climatic classification system, which predicts the global distribution of biomes based on monthly precipitation and average temperatures. In this study, the Köppen classification is used to evaluate the impacts of the melting of the Greenland and Antarctic Ice Sheets on GCM simulation results, on regional and global scales. To assess the impacts of accelerated ice sheet melting, an approach is utilized which is based on numerical simulations from the IPSL-CM5A-LR GCM; here, freshwater is introduced near the ice sheets and is superimposed on the RCP8.5 scenario. The changes in the distribution of the Köppen climatic regions under various scenarios (a historical run from observations, RCP8.5, and various examples of polar ice sheet melting) and comparisons between them reveal that major changes will occur on the global scale during the period 2041–2060. The analysis of group shifts within the Köppen classification system reveals that when freshwater from Greenland or Antarctica is introduced into the ocean, the inter-tropical belt undergoes greater change than it does under the RCP8.5 scenario. A focus on sub-group shifts within the Koppen classification system shows that changes in precipitation have major impacts on the climate in the Southern Hemisphere. Further, the changes are more drastic if the freshwater originates from Greenland than from Antarctica or from both locations. However, changes in temperature strongly impact the climate in the Northern Hemisphere and are significantly affected by the melting of the Greenland Ice Sheet. This study highlights the importance of considering ice sheet melting in the modeling of future global climate

Singular Extreme Events and Their Attribution to Climate Change: A Climate Service–Centered Analysis

International audienceExtreme event attribution (EEA) proposes scientific diagnostics on whether and how a specific weather event is (or is not) different in the actual world from what it could have been in a world without climate change. This branch of climate science has developed to the point where European institutions are preparing the ground for an operational attribution service. In this context, the goal of this article is to explore a panorama of scientist perspectives on their motivations to undertake EEA studies. In order to do so, we rely on qualitative semi-structured interviews of climate scientists involved in EEA, on peer-reviewed social and climate literature discussing the usefulness of EEA and on reports from the EUCLEIA project, which investigated the possibility of building an EEA service. We propose a classification of EEA’s potential uses and users and discuss each of them. We find that, first, there is a plurality of motivations and that individual scientists disagree on which one is most useful. Second, there is a lack of solid, empirical evidence to back up any of these motivations

Phytoseiid mites (Acari) are bio-indicators of agricultural practice impact on the agroecosystem functioning

National audienc