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1. Effect of climate change, CO2 trends, nitrogen addition, and land-cover and management intensity changes on the carbon balance of European grasslands.

Author

Chang J, Ciais P, Viovy N, Vuichard N, Herrero M, Havlík P, Wang X, Sultan B, and Soussana JF

Subjects
Air Pollution, Animals, Carbon chemistry, Carbon Dioxide, Europe, Livestock, Models, Theoretical, Nitrogen chemistry, Soil chemistry, Agriculture methods, Carbon Cycle, Climate Change, Grassland
Abstract

Several lines of evidence point to European managed grassland ecosystems being a sink of carbon. In this study, we apply ORCHIDEE-GM a process-based carbon cycle model that describes specific management practices of pastures and the dynamics of carbon cycling in response to changes in climatic and biogeochemical drivers. The model is used to simulate changes in the carbon balance [i.e., net biome production (NBP)] of European grasslands over 1991-2010 on a 25 km × 25 km grid. The modeled average trend in NBP is 1.8-2.0 g C m(-2)  yr(-2) during the past two decades. Attribution of this trend suggests management intensity as the dominant driver explaining NBP trends in the model (36-43% of the trend due to all drivers). A major change in grassland management intensity has occurred across Europe resulting from reduced livestock numbers. This change has 'inadvertently' enhanced soil C sequestration and reduced N2 O and CH4 emissions by 1.2-1.5 Gt CO2 -equivalent, offsetting more than 7% of greenhouse gas emissions in the whole European agricultural sector during the period 1991-2010. Land-cover change, climate change and rising CO2 also make positive and moderate contributions to the NBP trend (between 24% and 31% of the trend due to all drivers). Changes in nitrogen addition (including fertilization and atmospheric deposition) are found to have only marginal net effect on NBP trends. However, this may not reflect reality because our model has only a very simple parameterization of nitrogen effects on photosynthesis. The sum of NBP trends from each driver is larger than the trend obtained when all drivers are varied together, leaving a residual - nonattributed - term (22-26% of the trend due to all drivers) indicating negative interactions between drivers., (© 2015 John Wiley & Sons Ltd.)

Published
2016
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4. Risques climatiques et agriculture en Afrique de l’Ouest

Author

Ba, Alassane, Bacyé, Bernard, Bader, Jean-Claude, Bama Nati, Aïssata Delphine, Bandaogo, Alimata A., Barbier, Bruno, Bossa, Aymar Y, Bossa, Aymar Yaovi, Cissé, Madiama, Compaore, Halidou, Coulibaly, Doubangolo, Coulibaly, Kalifa, Da, Arnold S., Da, Evariste D., Dabiré, Der, Dabire, Ernest, Dabiré, Nab, Daku, Elidaa K., Dama-Balima, Mariam Myriam, Dama Balima, Mariam Myriam, Dembele, Bandiougou, Dia, Djiby, Diarisso, Tidiane, Dieye, Mohamadou, Dingkhun, Michael, Diop, Abdou Ndiaye, Dorée, Augustine, Dossoumou, Nadège I. P., Douanio, Manaka, Doumbia, Mohamed, Fall, Cheickh Sadibou, Fayama, Tionyélé, Fusillier, Jean-Louis, Ganaba, Aida, Guiro, Aboudramane, Hien, Koufanou, Hien, Séverin, Hounkpè, Jean, Ilboudo, Sylvain, Kamissoko, Sayon, Kanadjigui, Youssouf, Keita, Amadou, Koné, Aboubakary S., Kouakou, Patrice, Kouressy, Mamoutou, Lavigne Delville, Philippe, Lawson, Namo K. Z., Lawson, Namo Z., Lidon, Bruno, Mboungou, Moise Damba, Nacro, Hassan B., Ndiaye, Mamadou, Ndiaye, Ramatoulaye, Ndiaye Diop, Abdou, Ndongo, Houleymatou, Ouattara, Baba, Ouattara, Maïmouna, Ouédraogo, Souleymane, Paturel, Jean-Emmanuel, Robin, Justine, Saba, Fatimata, Sadibou Fall, Cheickh, Salack, Seyni, Saley, Inoussa Abdou, Sall, Mamadou, Sanfo, Safietou, Sanogo, Sékouba, Sanon, Moussa, Sawadogo, Abdraime, Serpantié, Georges, Sine, Bassirou, Sissoko, Aliou, Sissoko, Fagaye, Sissoko, Salifou, Somé, Fabrice, Somé, Fourvouon, Sultan, Benjamin, Sylla, El Hadji Malick, Tékété, Mohamed L., Témé, Niaba, Théra, Korotimi, Torou, Bio M., Traore, Adama, Traore, Amadou, Traoré, Mamadou, Traoré, Sandrine, Vaksmann, Michel, Waongo, Moussa, Worou, Omonlola N., Yaméogo, Thomas, Yameogo, Thomas B., Yira, Yacouba, Sultan, Benjamin, Bossa, Aymar Yaovi, Salack, Seyni, and Sanon, Moussa

Subjects
alimentation, climatologie, Economics, Environmental Studies, Afrique de l’Ouest, risques, écologie, agronomie, ressources, changements climatiques, BUS072000, RNU, eau, agriculture, développement
Abstract

Le futur de l’Afrique de l’Ouest dépend de la capacité du secteur de l’agriculture à s’adapter pour garantir la sécurité alimentaire dans un contexte de changement climatique et de croissance démographique. Pour faciliter cette adaptation, la recherche a déployé d’importants efforts pour améliorer les connaissances sur les mécanismes climatiques et leurs impacts sur les systèmes agropastoraux. Or, ces avancées issues de la recherche ne sont que rarement prises en compte dans la planification et la prise de décision. Partant de ce constat, un projet de recherche « Agriculture et gestion des risques climatiques : outils et recherches en Afrique », soutenu par le ministère français des Affaires étrangères et du Développement international est mené entre 2016 et 2018 dans plusieurs pays d’Afrique de l’Ouest. Il a pour objectif d’élaborer des outils efficaces de gestion du risque climatique pour les agriculteurs, en co-construisant avec des réseaux de chercheurs et d’acteurs directement impliqués dans l’accompagnement de l’agriculture des stratégies innovantes basées sur les résultats de la recherche. Cet ouvrage restitue les principales avancées de cette recherche-action sur trois thématiques prioritaires : les services climatiques pour l’agriculture, la gestion des ressources en eau et l’intensification écologique. Il permet aux acteurs du secteur agricole (organisations paysannes, filières, secteur privé agricole, banques de développement agricole, fournisseurs d’intrants, services agricoles et de météorologie) de s’approprier de nouvelles connaissances et de nouveaux outils pour une meilleure prise en compte des risques climatiques dans la gestion des systèmes de production.

Published
2020

5. Introduction générale

Author

Sultan, Benjamin, Bossa, Aymar Yaovi, Salack, Seyni, and Sanon, Moussa

Subjects
alimentation, climatologie, Economics, Environmental Studies, Afrique de l’Ouest, risques, écologie, agronomie, ressources, changements climatiques, BUS072000, RNU, eau, agriculture, développement
Abstract

Le futur de l’Afrique de l’Ouest, son équilibre économique, politique et social dépendent de la capacité du secteur de l’agriculture à s’adapter pour garantir la sécurité alimentaire dans un contexte de pressions multiples comme celles engendrées par le changement climatique et la croissance démographique. Pour faciliter cette adaptation, la recherche a déployé d’importants efforts ces dernières années en améliorant la connaissance sur la compréhension des changements climatiques en Afrique d...

Published
2020

8. Hydrological extremes and food security in western Amazon

Author

ronchail, josyane, Schor, Tatiana, Moraes, Andre, Pinto, Moises, Sabot , Manon, Pinheiro, Heitor, Espinoza Villar, Jhan Carlo, Drapeau, Guillaume, Quirion, Philippe, Guyot, Jean-Loup, Filizola, Naziano, Sultan, Benjamin, Martinez, Jean-Michel, Processus de la variabilité climatique tropicale et impacts (PARVATI), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris Diderot - Paris 7 (UPD7), University of the Amazonas State, Université Pierre et Marie Curie - Paris 6 (UPMC), Universidad Nacional Agraria La Molina (UNALM), Institut Pierre-Simon-Laplace (IPSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), centre international de recherche sur l'environnement et le développement (CIRED), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École des hautes études en sciences sociales (EHESS)-AgroParisTech-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École des hautes études en sciences sociales (EHESS)-AgroParisTech-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)

Subjects
[SDE.MCG]Environmental Sciences/Global Changes, hydrology, Amazon basin, food security, [SHS.GEO]Humanities and Social Sciences/Geography, hydrological cycle, hydrological extremes, [SDE.ES]Environmental Sciences/Environmental and Society, agriculture
Abstract

International audience; The water level of the Amazon and of its tributaries varies significantly from one season to another. For instance, at Iquitos station (Peru), the water level varies from 18 meters in May-June to 8 meters in September-October. That is why, during the low-flow period, cultivating becomes possible and is important on the riverbanks and in the inundation plains. Agricultural production in a family-based system on the riverbanks and inundation plains is very important in terms of guarantee of supply for food security. In order to understand the important relation between agriculture, food security and hydrological system some characteristics of the local agriculture in the Amazonian region located between Iquitos (Peru) and the triple frontier between Brazil, Peru and Colombia are first presented using results from field observations, survey and data from the Peruvian and Brazilian Agricultural agencies. Then, information about the interannual variability (1980-2014) of the hydrological cycle of the Solimões River are presented: discussion and definition of the dates of the beginning and of the end of the low-flow period, duration of the low flow period, velocity of the water level changes during the increasing and decreasing flow periods, presence of “false alarm” at the beginning or at the end of the dry and the wet period, … This part is developed using water level data from the national hydrological services of Peru and Brazil and from the Environmental Research Observatory SOHYBAM (Geodynamical, hydrological and biogeochemical control of erosion/alteration and material transport in the Amazon basin). Finally, as a shorter than usual length of the low flow season, a rapid increase of the water level, a “false” beginning of the low water season, etc. are hazards that may put at risk sowing and plant development, hydrological parameters are related to yield values seeking possible correlations between extreme events and food security in the region.

Published
2015

9. Direct and indirect effects of CO2 increase on crop yield in West Africa.

Author

Sultan, Benjamin, Parkes, Ben, and Gaetani, Marco

Subjects
*CLIMATE change, *RADIATIVE forcing
Abstract

Climate change directly threatens food security in West Africa through a negative impact on productivity of the main staple food crops. However, providing consistent future crop yield projections in the region remains challenging because of uncertainty in the response of the regional climate to the CO2 increase and in the response of the cultivated crop to this altered climate with more CO2 in the atmosphere. Here, we analyse a set of idealized climate simulations to investigate the effect of CO2 concentration increase on the West African monsoon and potential impacts on crop yields of maize. On the one hand, simulations with prescribed SST and quadrupled CO2 concentration are analysed to study the atmospheric response to direct radiative forcing induced by increasing CO2 concentration, not mediated by ocean heat capacity. On the other hand, simulations with prescribed SST augmented by 4 K are analysed to study the atmospheric response to the global ocean warming expected as a consequence of the increasing CO2 radiative forcing. We show that if CO2 concentration increase has a positive impact on crop yield due to the fertilization effect, it also has a direct effect on the monsoon which acts to increase (decrease) rainfall in the eastern (western) part of the Sahel and increase (decrease) crop yields consequently. Finally, we show that SST warming acts to reduce rainfall and increase local temperatures leading to strong reduction of crop yield. The reduction of crop yield is more important in the eastern part of the Sahel where the warming is more intense than in the western part of the Sahel. Overall, positive effects are weaker and more uncertain than the negative effects in the analysed simulations. Crop yield response to rainfall and temperature variations in the GLAM model. Pixel by pixel difference against the domain average for mean yield and total growing season rainfall (left) and mean temperature (right). Values are then averaged over the 30 years of the control experiment to give more than 400 values expressed in percentage. [ABSTRACT FROM AUTHOR]

Published
2019
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10. Adaptability of Mediterranean Agricultural Systems to Climate Change: The Example of the Sierra Mágina Olive-Growing Region (Andalusia, Spain). Part II: The Future

Author

ANGLES, Stephane, ronchail, josyane, Cohen, Marianne, Alonso-Roldán, María, Garcin, Hélène, Sultan, Benjamin, Angles, Stéphane, Université Paris Diderot - Paris 7 (UPD7), Processus de la variabilité climatique tropicale et impacts (PARVATI), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), Espaces, Nature et Culture (ENeC), Université Paris-Sorbonne (UP4)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Dynamiques Sociales et Recomposition des Espaces (LADYSS), Centre National de la Recherche Scientifique (CNRS)-Université Panthéon-Sorbonne (UP1)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris Nanterre (UPN)-Université Paris Diderot - Paris 7 (UPD7), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris Nanterre (UPN)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris Diderot - Paris 7 (UPD7)-Université Paris Nanterre (UPN)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Panthéon-Sorbonne (UP1)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche en Géographie (LOTERR), Université de Lorraine (UL), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)

Subjects
2. Zero hunger, Atmospheric Science, Global and Planetary Change, [SDE.MCG]Environmental Sciences/Global Changes, Agriculture, [SHS.GEO]Humanities and Social Sciences/Geography, 15. Life on land, Europe, Geographic information systems (GIS), 13. Climate action, Climate change, Communications/decision making, Ensembles, ComputingMilieux_MISCELLANEOUS, Social Sciences (miscellaneous)
Abstract

The adaptability of olive-growing systems to climate change is studied in the Sierra Mágina region (Andalusia) using an interdisciplinary approach that evaluates and makes associations across climate, water resources, and socioeconomic strategies. First, the evolution of rainfall and temperature during the twenty-first century is assessed at the local scale using 17 regional climate model (RCM) simulations. A 15%–30% rainfall reduction is expected in the fall combined with a 7%–9% annual reduction by 2030–50. Based on a regression model relating yields to rainfall, residual yields (independent of the increasing trend in the present period and from the biennial fruit bearing of the olive tree) are projected to decrease by 7% and 3.5% by 2030–50 for rainfed and irrigated olive groves, respectively. Substantial uncertainties in these results are discussed. A GIS analysis shows a reduction of ground and surface water resources, which are the basis of the present adaptation to rainfall variability, and an uneven potential for adaptation to climate change in the Sierra Mágina region. Despite the important challenges faced by this rural region, there is no consensus among the local key actors regarding adaptation strategies. This is due in part to the diversity among farmers, but also to the different levels of awareness about climate change among all the stakeholders and farmers. Since the projected decline in medium-range future yields is not very high, there might be time and possibilities, especially in the northern part of the Sierra Mágina, to build a local adaptability strategy within the next 20 years that would take into account improved methods of water management and a better economic valorization of olive oil. But at longer time scales, the adaptability of the olive-growing system to yield and water resource declines seems to be threatened.

Published
2014

11. An ex-ante evaluation of the use of seasonal climate forecasts for millet growers in SW Niger

Author

Roudier, Philippe, Sultan, Benjamin, Quirion, Philippe, Baron, Christian, Alhassane, Agali, Traoré, Seydou B., Muller, Bertrand, Centre International de Recherche sur l'Environnement et le Développement (CIRED), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École des hautes études en sciences sociales (EHESS)-AgroParisTech-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), Territoires, Environnement, Télédétection et Information Spatiale (UMR TETIS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-AgroParisTech-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Centre Régional AGRHYMET (CRA), Amélioration génétique et adaptation des plantes méditerranéennes et tropicales (UMR AGAP), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro), R2DS et REGYNA, Financement projet REGYNA, réseau R2DS, centre international de recherche sur l'environnement et le développement (CIRED), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École des hautes études en sciences sociales (EHESS)-AgroParisTech-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-AgroParisTech-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), and Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)

Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences, P40 - Météorologie et climatologie, millet, Gestion du risque, PRODUCTION AGRICOLE, PLANTE CULTIVEE, seasonal forecast, F01 - Culture des plantes, Niger, Pennisetum glaucum, SEMIS, agriculture, Changement climatique, MODELE MATHEMATIQUE, SAISON HUMIDE, Précipitation, U10 - Informatique, mathématiques et statistiques, Modélisation des cultures, PREVISION CLIMATIQUE, risk aversion, MILLET, Rendement des cultures, PRECIPITATION, PLUIE, FERTILISATION DU SOL, Africa, Prévision météorologique
Abstract

International audience; This work assesses the value of climate forecasts for millet growers in Niger. We quantify the potential value of three kinds of categorical forecasts assigning cumulated rainfall during the forthcoming rainy season by tercile (dry, normal or humid): (i) a realistic imperfect tercile forecast; (ii) a perfect tercile forecast and (iii) a perfect tercile forecast which includes a prediction of rainy season onset and offset dates. Eighteen management strategies are assessed. Corresponding yields are computed using the SARRA-H crop model then converted into utility by taking into account risk-aversion. Simulations over an historical 18-year period 1990-2007 show that benefit is lowest with imperfect tercile forecasts (+6.9 %), higher (+11%) with perfect tercile forecasts, and reaches +31% when enhanced adaptation strategies and additional climatic indices are available. These results show that improving existing forecast systems by including the prediction of onset and cessation of rainfall is of great value.

Published
2012

12. Représentation de la pluie dans les modèles régionaux de climat et application à l'estimation des rendements du mil au Sénégal

Author

Salack, Seyni, Sultan, Benjamin, Oettli, Pascal, Muller, Bertrand, Gaye, Amadou T., and Hourdin, Frédéric

Subjects
Modèle, Zone agroclimatique, RENDEMENT, AGRICULTURE, P40 - Météorologie et climatologie, Pluie, PLUVIOMETRIE, F01 - Culture des plantes, Pennisetum glaucum, Changement climatique, MIL, U10 - Informatique, mathématiques et statistiques, Modélisation des cultures, MODELISATION, Rendement des cultures, CLIMAT, MODELE REGIONAL, CHANGEMENT CLIMATIQUE, Modèle mathématique, Pluviomètre, METHODOLOGIE
Abstract

Les très fortes répercussions des aléas climatiques sur l'agriculture et la sécurité alimentaire en Afrique subsaharienne, auxquelles se rajoute la perspective du changement climatique, ont poussé la communauté scientifique à documenter les impacts du climat dans cette région. Cependant, si la plupart des études quantifiant les impacts du climat se basent sur des sorties de modèles régionaux de climat, très peu font part de l'incertitude associée à leur utilisation. Pourtant le choix d'un modèle régional plutôt qu'un autre, voire même d'une paramétrisation plutôt qu'une autre, peut influer fortement sur le résultat final car les modèles agronomiques sont très sensibles à la qualité du forçage climatique en entrée. L'objectif de cette étude est d'explorer cette question en analysant la dispersion de la représentation des pluies issues d'un ensemble de huit modèles régionaux et la façon dont cette dispersion se traduit dans l'estimation des rendements du mil au Sénégal, simulés par le modèle agronomique SARRAH. L'étude montre qu'il existe une grande dispersion dans la représentation de la pluviométrie d'un modèle régional à l'autre (et même pour un même modèle régional avec deux jeux de paramètres différents) tant à l'échelle saisonnière qu'à l'échelle intrasaisonnière. Ces biais introduisent des erreurs importantes dans l'estimation des impacts agronomiques. Ces erreurs peuvent être à même d'invalider des conclusions sur les impacts du changement climatique basés sur l'utilisation d'un seul modèle régional. L'utilisation de méthodes de correction de biais s'avère ainsi indispensable.

Published
2012

14. A bias-corrected CMIP5 dataset for Africa using CDF-t method. A contribution to agricultural impact studies.

Author

Famien, Adjoua Moise, Janicot, Serge, Ochou, Abe Delfin, Vrac, Mathieu, Defrance, Dimitri, Sultan, Benjamin, and Noël, Thomas

Subjects
AGRICULTURAL climatology, CLIMATE change, AGRICULTURE
Abstract

The objective of this paper is to present a new data set of bias-corrected CMIP5 global climate models (GCMs) daily data over Africa. This dataset was obtained in using the Cumulative Distribution Function Transform (CDF-t) method, a method that has been applied on several regions and contexts but never on Africa. Here CDF-t is used over the period 1950–2099 combining historical runs and climate change scenarios on 6 variables, precipitation, mean near-surface air temperature, near-surface maximum air temperature, near-surface minimum air temperature, surface down-welling shortwave radiation, and wind speed, which are critical variables for agricultural purposes. Evaluation of the results is carried out over West Africa on a list of priority users-based metrics that was discussed and selected with stakeholders and on simulated yield using a crop model simulating maize growth. Bias-corrected GCMs data are compared with another available dataset of bias-corrected GCMs, and the impact of three different reference datasets on bias-corrections is also examined in details. CDF-t is very effective in removing the biases and in reducing the high inter-GCMs scattering. Differences with other bias-corrected GCMs data are mainly due to the differences between the reference datasets. This is particular true for surface down-welling shortwave radiation, which has impacts in terms of simulated maize yields. Projections of future yields over West Africa have quite different levels, depending on bias-correction method used, but they all show a similar relative decreasing trend over the 21st century. [ABSTRACT FROM AUTHOR]

Published
2017
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15. Assessing climate adaptation options and uncertainties for cereal systems in West Africa.

Author

Guan, Kaiyu, Sultan, Benjamin, Biasutti, Michela, Baron, Christian, and Lobell, David B.

Subjects
*GRAIN, *AGRICULTURE, *FOOD security, *AGRICULTURAL climatology, *WATER harvesting, ADAPTATION
Abstract

In the coming decades, the already fragile agricultural system in West Africa will face further challenges in meeting food security, both from increasing population and from the impacts of climate change. Optimal prioritization of adaptation investments requires the assessment of various possible adaptation options and their uncertainties; successful adaptations of agriculture to climate change should not only help farmers deal with current climate risks, but also reduce negative (or enhance positive) impacts associated with climate change using robust climate projections. Here, we use two well-validated crop models (APSIM v7.5 and SARRA-H v3.2) and an ensemble of downscaled climate forcing from the CMIP5 models to assess five possible and realistic adaptation options for the production of the staple crop sorghum ( Sorghum bicolor Moench .): (i) late sowing, (ii) intensification of seeding density and fertilizer use, (iii) increasing cultivars’ thermal time requirement, (iv) water harvesting, and (v) increasing resilience to heat stress during the flowering period. We adopt a new assessment framework to account for both the impacts of proposed adaptation options in the historical climate and their ability to reduce the impacts of future climate change, and we also consider changes in both mean yield and inter-annual yield variability. We target the future period of 2031–2060 for the “business-as-usual” scenario (RCP8.5), and compare with the historical period of 1961–1990. Our results reveal that most proposed “adaptation options” are not more beneficial in the future than in the historical climate (−12% to +4% in mean yield), so that they do not really reduce the climate change impacts. Increased temperature resilience during the grain number formation period is the main adaptation that emerges (+4.5%). Intensification of fertilizer inputs can dramatically benefit yields in the historical/current climate (+50%), but does not reduce negative climate change impacts except in scenarios with substantial rainfall increases. Water harvesting contributes to a small benefit in the current climate (+1.5% to +4.0%) but has little additional benefit under climate change. Our analysis of uncertainties arising from crop model differences (conditioned on the used model versions) and various climate model projections provide insights on how to further constrain uncertainties for assessing future climate adaptation options. [ABSTRACT FROM AUTHOR]

Published
2017
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16. La variabilité climatique en Afrique de l'Ouest aux échelles saisonnière et intra-saisonnière : II : applications à la sensibilité des rendements agricoles au Sahel

Author

Sultan, Benjamin, Baron, Christian, Dingkuhn, Michaël, Sarr, Benoit, and Janicot, Serge

Subjects
Modèle, Zone agroclimatique, P40 - Météorologie et climatologie, Pluviométrie, F62 - Physiologie végétale - Croissance et développement, Climat de mousson, rendement, F01 - Culture des plantes, Mesure, Pennisetum glaucum, Hydrologie, date de semis, Expérimentation, Agriculture, Variation saisonnière, Climatologie
Abstract

L'agriculture au Sahel, dans la seule région du monde où la production vivrière par habitant diminue, occupe une place très importante dans tous les projets gouvernementaux, et assurer un certain degré de stabilité des rendements des récoltes aux agriculteurs est devenu une priorité nationale pour les institutions de recherche de l'Afrique de l'Ouest. L'eau est un facteur de rendement capital. Pour une gestion optimale des ressources en eau, il est apparu nécessaire de décrire et de comprendre le cycle saisonnier de la mousson au Sahel. A partir d'une étude régionale de la mousson, des événements majeurs ont été identifiés comme marquant la mise en place de la mousson d'une part, et l'occurrence de séquences sèches au coeur de la saison humide, d'autre part. Le but de ce travail est de mesurer l'impact de ces événements à grande échelle sur le rendement à l'échelle locale. Cette première approche pour relier l'échelle climatique régionale et la parcelle a été menée au moyen d'expériences de sensibilité sur un modèle agronomique SARRAH (Système d'analyse régionale de risques agroclimatiques) qui simule la réponse du rendement à la contrainte hydrique. Ces expériences visent à mesurer la sensibilité du rende-ment potentiel (limité par le climat mais non par les ressources minérales) à la date de semis pour la culture du mil à Niamey sur la période 1968-1990. La variabilité du rendement potentiel au sein des différentes simulations est discutée pour tenter d'extraire les différentes causes de cette variabilité: validité du critère de décision pour le choix de la date de semis, rôle de la variabilité interannuelle, et impact des épisodes secs au coeur de la saison humide. On montre alors l'apport de l'étude régionale de la mousson pour améliorer le rendement agricole à l'échelle de la parcelle.

Published
2005

17. Agriculture in West Africa in the Twenty-First Century: Climate Change and Impacts Scenarios, and Potential for Adaptation.

Author

Sultan, Benjamin and Gaetani, Marco

Subjects
CLIMATE change research, AGRICULTURAL research
Abstract

West Africa is known to be particularly vulnerable to climate change due to high climate variability, high reliance on rain-fed agriculture, and limited economic and institutional capacity to respond to climate variability and change. In this context, better knowledge of how climate will change in West Africa and how such changes will impact crop productivity is crucial to inform policies that may counteract the adverse effects. This review paper provides a comprehensive overview of climate change impacts on agriculture in West Africa based on the recent scientific literature. West Africa is nowadays experiencing a rapid climate change, characterized by a widespread warming, a recovery of the monsoonal precipitation, and an increase in the occurrence of climate extremes. The observed climate tendencies are also projected to continue in the twenty-first century under moderate and high emission scenarios, although large uncertainties still affect simulations of the future West African climate, especially regarding the summer precipitation. However, despite diverging future projections of the monsoonal rainfall, which is essential for rain-fed agriculture, a robust evidence of yield loss in West Africa emerges. This yield loss is mainly driven by increased mean temperature while potential wetter or drier conditions as well as elevated CO2 concentrations can modulate this effect. Potential for adaptation is illustrated for major crops in West Africa through a selection of studies based on process-based crop models to adjust cropping systems (change in varieties, sowing dates and density, irrigation, fertilizer management) to future climate. Results of the cited studies are crop and region specific and no clear conclusions can be made regarding the most effective adaptation options. Further efforts are needed to improve modeling of the monsoon system and to better quantify the uncertainty in its changes under a warmer climate, in the response of the crops to such changes and in the potential for adaptation. [ABSTRACT FROM AUTHOR]

Published
2016
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18. Adaptability of Mediterranean Agricultural Systems to Climate Change: The Example of the Sierra Mágina Olive-Growing Region (Andalusia, Spain). Part II: The Future.

Author

Ronchail, Josyane, Cohen, Marianne, Alonso-Roldán, María, Garcin, Hélène, Sultan, Benjamin, and Angles, Stéphane

Abstract

The adaptability of olive-growing systems to climate change is studied in the Sierra Mágina region (Andalusia) using an interdisciplinary approach that evaluates and makes associations across climate, water resources, and socioeconomic strategies. First, the evolution of rainfall and temperature during the twenty-first century is assessed at the local scale using 17 regional climate model (RCM) simulations. A 15%-30% rainfall reduction is expected in the fall combined with a 7%-9% annual reduction by 2030-50. Based on a regression model relating yields to rainfall, residual yields (independent of the increasing trend in the present period and from the biennial fruit bearing of the olive tree) are projected to decrease by 7% and 3.5% by 2030-50 for rainfed and irrigated olive groves, respectively. Substantial uncertainties in these results are discussed. A GIS analysis shows a reduction of ground and surface water resources, which are the basis of the present adaptation to rainfall variability, and an uneven potential for adaptation to climate change in the Sierra Mágina region. Despite the important challenges faced by this rural region, there is no consensus among the local key actors regarding adaptation strategies. This is due in part to the diversity among farmers, but also to the different levels of awareness about climate change among all the stakeholders and farmers. Since the projected decline in medium-range future yields is not very high, there might be time and possibilities, especially in the northern part of the Sierra Mágina, to build a local adaptability strategy within the next 20 years that would take into account improved methods of water management and a better economic valorization of olive oil. But at longer time scales, the adaptability of the olive-growing system to yield and water resource declines seems to be threatened. [ABSTRACT FROM AUTHOR]

Published
2014
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19. How satellite rainfall estimate errors may impact rainfed cereal yield simulation in West Africa.

Author

Ramarohetra, Johanna, Sultan, Benjamin, Baron, Christian, Gaiser, Thomas, and Gosset, Marielle

Subjects
*RAINFALL, *DRY farming, *SAMPLING errors, *GRAIN yields, *WEATHER forecasting, *SIMULATION methods & models, *AGRICULTURAL forecasts
Abstract

Highlights: [•] We simulate crop yield using state-of-the-art satellite rainfall estimates. [•] Satellite data use can introduce large biases in crop yield predictions. [•] Biases differ strongly among the four crops considered in two sites. [•] Biases are not simple extrapolation of each satellite product total rainfall biases. [•] A realistic distribution of rainfall can be very important for crop yield prediction. [Copyright &y& Elsevier]

Published
2013
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20. The impact of future climate change on West African crop yields: What does the recent literature say?

Author

Roudier, Philippe, Sultan, Benjamin, Quirion, Philippe, and Berg, Alexis

Subjects
CLIMATE change, CROP yields, DRY farming, ECONOMIC sectors, AGRICULTURAL productivity, TEMPERATURE effect, RAINFALL
Abstract

Abstract: In West Africa, agriculture, mainly rainfed, is a major economic sector and the one most vulnerable to climate change. A meta-database of future crop yields, built up from 16 recent studies, is used to provide an overall assessment of the potential impact of climate change on yields, and to analyze sources of uncertainty. Despite a large dispersion of yield changes ranging from −50% to +90%, the median is a yield loss near −11%. This negative impact is assessed by both empirical and process-based crop models whereas the Ricardian approach gives very contrasted results, even within a single study. The predicted impact is larger in northern West Africa (Sudano-Sahelian countries, −18% median response) than in southern West Africa (Guinean countries, −13%) which is likely due to drier and warmer projections in the northern part of West Africa. Moreover, negative impacts on crop productivity increase in severity as warming intensifies, with a median yield loss near −15% with most intense warming, highlighting the importance of global warming mitigation. The consistently negative impact of climate change results mainly from the temperature whose increase projected by climate models is much larger relative to precipitation change. However, rainfall changes, still uncertain in climate projections, have the potential to exacerbate or mitigate this impact depending on whether rainfall decreases or increases. Finally, results highlight the pivotal role that the carbon fertilization effect may have on the sign and amplitude of change in crop yields. This effect is particularly strong for a high carbon dioxide concentration scenario and for C3 crops (e.g. soybean, cassava). As staple crops are mainly C4 (e.g. maize, millet, sorghum) in WA, this positive effect is less significant for the region. [Copyright &y& Elsevier]

Published
2011
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21. Including tropical croplands in a terrestrial biosphere model: application to West Africa.

Author

Berg, Alexis, Sultan, Benjamin, and Noblet-Ducoudré, Nathalie

Subjects
AGRICULTURAL climatology, FARMS, VEGETATION & climate, MONSOONS, AGRICULTURE
Abstract

Studying the large-scale relationships between climate and agriculture raises two different issues: the impact of climate on crops, and the potential feedbacks to climate from croplands. A relevant and consistent framework to address this twofold issue is to extend existing Dynamic Global Vegetation Models, which can be coupled to climate models, in order to explicitly account for croplands. Here we present the first results of such a strategy applied to tropical croplands over West Africa. We introduce into the terrestrial biosphere model ORCHIDEE (IPSL) adequate processes and parameterisations taken from the crop model SARRAH (CIRAD), which is calibrated for millet over this region. The resulting model, ORCH-mil, realistically simulates the growth and yield of millet when tested on an experimental station in Senegal. The model is then applied over West Africa using a 36-year climate reanalysis dataset. First the model is tested in terms of yield simulation, against national millet yields from the FAO database. The ability of the model to reproduce the spatial and temporal variability of millet yields is assessed. Then, the effects on land surface fluxes of explicitly accounting for croplands are examined: significant differences between ORCH-mil and ORCHIDEE appear, through changes in sensible and latent heat fluxes, surface albedo, and water resources. These differences encompass a potential impact on the monsoon system, mainly during the retreat of monsoon rains. [ABSTRACT FROM AUTHOR]

Published
2011
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22. Medium Lead-Time Predictability of Intraseasonal Variability of Rainfall in West Africa.

Author

Sultan, Benjamin, Janicot, Serge, and Correia, Cyrille

Subjects
*AGRICULTURE, *RAINFALL, *MONSOONS, *WEATHER forecasting
Abstract

The variability of the West African monsoon on the intraseasonal time scale is a major issue for agricultural strategy, as the occurrence of dry spells can strongly impact yields of rain-fed crops. This study investigates this intraseasonal variability of rainfall over West Africa and gives a first overview of its predictability at a medium lead time. A statistical method, the singular spectrum analysis, is applied to a ground-based rainfall index in West Africa to describe first temporal patterns of the main leading modes of intraseasonal variability. The results point out the existence of one oscillatory mode of 34 days, one of 20 days, and one of 14 days. The same methodology is applied to rainfall from two reanalysis datasets and to deep convection from satellite data in order to assess the accuracy of the representation of intraseasonal variability in these datasets. It is shown that although the day-to-day variability of rainfall is not well captured in these datasets, intraseasonal features and, in particular, the low-frequency mode are very well reproduced. The medium lead-time predictability (5–10 days) of the intraseasonal modes is investigated using both the dynamical forecast scheme of the ECMWF and a statistical method, the maximum entropy method. For the latter method, an operational application using unfiltered input data is also considered. The performance of these prediction schemes is compared using a simple reference technique in which forecasts are based entirely on persistence. It is found that statistical predictions are much more promising than the dynamical ones, though they encounter problems when applied operationally. In an operational application, the forecast skill for the 10–90-day intraseasonal band is low but the predictability of individual intraseasonal modes is higher. The stability of the forecast skill levels is influenced by the characteristics of the intraseasonal mode. When the characteristics (i.e., amplitude and period) of the considered intraseasonal mode are well defined, skillful forecasts can be obtained. However, when the characteristics change rapidly, the forecast fails. [ABSTRACT FROM AUTHOR]

Published
2009
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23. Price vs. weather shock hedging for cash crops: Ex ante evaluation for cotton producers in Cameroon.

Author

Leblois, Antoine, Quirion, Philippe, and Sultan, Benjamin

Subjects
*RAINFALL, *COTTON farmers, *AGRICULTURE, *RISK assessment, *ENVIRONMENTAL indicators, *COTTON growing, *WEATHER insurance, *CROP yields, *AGRICULTURE & the environment
Abstract

In the Sudano–Sahelian zone, which includes Northern Cameroon, the inter-annual variability of the rainy season is high and irrigation scarce. As a consequence, bad rainy seasons have a detrimental impact on crop yield. In this paper, we assess the risk mitigation capacity of weather index-based insurance for cotton farmers. We compare the ability of various indices, mainly based on daily rainfall, to increase the expected utility of a representative risk-averse farmer. We first give a tractable definition of basis risk and use it to show that weather index-based insurance is associated with a large basis risk, whatever the index considered. It has thus limited potential for income smoothing, a conclusion which is robust to the utility function. Second, in accordance with the existing agronomical literature we find that the length of the cotton growing cycle, in days, is the best performing index considered. Third, we show that using observed cotton sowing dates to define the length of the growing cycle significantly decreases the basis risk, compared to using simulated sowing dates. Finally we find that the gain of the weather-index based insurance is lower than that of hedging against cotton price fluctuations provided by the national cotton company. This casts doubt on the strategy of supporting weather–index insurances in cash crop sectors selling at international market prices without recommending any price stabilisation scheme. [Copyright &y& Elsevier]

Published
2014
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25. Partie 1. L’information agroclimatique pour l’aide à la décision

Author

Sultan, Benjamin, Bossa, Aymar Yaovi, Salack, Seyni, and Sanon, Moussa

Subjects
alimentation, climatologie, Economics, Environmental Studies, Afrique de l’Ouest, risques, écologie, agronomie, ressources, changements climatiques, BUS072000, RNU, eau, agriculture, développement
Published
2020

27. Rural societies in the face of climatic and environmental changes in West Africa

Author

Audouin, E., Vayssières, J., Odru, M., Masse, Dominique, Dorégo, G.S., Delaunay, Valérie, Lecomte, P., Sultan, Benjamin (ed.), Lalou, Richard (ed.), Amadou Sanni, M. (ed.), Oumarou, A. (ed.), and Soumaré, M.A. (ed.)

Subjects
SYSTEME AGRAIRE, AGRICULTURE, CHANGEMENT CLIMATIQUE, FERTILISATION DU SOL, ENQUETE AGRONOMIQUE, ELEVAGE, DEVELOPPEMENT RURAL, TERROIR, EXPLOITATION AGRICOLE, UTILISATION DU SOL, PRATIQUE CULTURALE
Published
2017

28. Réintroduire l'élevage pour accroître la durabilité des terroirs villageois d'Afrique de l'Ouest : le cas du bassin archidier au Sénégal

Author

Audouin, E., Vayssières, J., Odru, M., Masse, Dominique, Dorégo, S., Delaunay, Valérie, Lecomte, P., Sultan, Benjamin (ed.), Lalou, Richard (ed.), Amadou Sanni, M. (ed.), Oumarou, A. (ed.), and Soumaré, M.A. (ed.)

Subjects
AGRICULTURE, L01 - Élevage - Considérations générales, ENQUETE AGRONOMIQUE, Élevage, EXPLOITATION AGRICOLE, PRATIQUE CULTURALE, Développement régional, SYSTEME AGRAIRE, Développement durable, FERTILISATION DU SOL, MODELE CONCEPTUEL, DEVELOPPEMENT DURABLE, ELEVAGE, DEVELOPPEMENT RURAL, TERROIR, UTILISATION DU SOL
Published
2015

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