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Upwelling processes bring nutrient-rich waters from the deep ocean to the surface. Areas of upwelling are often associated with high productivity, offering great economic value in terms of fisheries. The sensitivity of spring/summer-time coastal upwelling systems to climate change has recently received a lot of attention. Several studies have suggested that their intensity may increase in the future while other authors have shown decreasing intensity in their equatorward portions. Yet, recent observations do not show robust evidence of this intensification. The Senegalo-Mauritanian upwelling system (SMUS) located at the southern edge of the north Atlantic system (12°N–20°N) and most active in winter/spring has been largely excluded from these studies. Here, the seasonal cycle of the SMUS and its response to climate change is investigated in the database of the Coupled Models Inter comparison Project Phase 5 (CMIP5). Upwelling magnitude and surface signature are characterized by several sea surface temperature and wind stress indices. We highlight the ability of the climate models to reproduce the system, as well as their biases. The simulations suggest that the intensity of the SMUS winter/spring upwelling will moderately decrease in the future, primarily because of a reduction of the wind forcing linked to a northward shift of Azores anticyclone and a more regional modulation of the low pressures found over Northwest Africa. The implications of such an upwelling reduction on the ecosystems and local communities exploiting them remains very uncertain.

AbstractThe aim of this study is to highlight the recent progress in mapping vector‐borne diseases in West Africa using modelling and field experiments. Based on climatic indicators, methods have been developed to map Rift Valley fever (RVF) and malaria risk. Modelling results corroborate that northern Senegal and southern Mauritania appear to be critical areas for RVF outbreaks and that the malaria epidemic fringe is located at the northern edge of the Sahel. Future projections highlight that the malaria risk decreases over northern Sahel. This is related to a southward shift of the potential epidemic belt in autumn. Copyright © 2010 Royal Meteorological Society

Climate change and variability are significant challenges for the environment and food security worldwide. Development strategies focusing simultaneously on adaptive farming, productivity, and reducing greenhouse gas (GHG) emissions-known as climate-smart agriculture (CSA) strategies-are key to responding to these challenges. For almost a decade, within the framework of Climate Change, Agriculture and Food Security (CCAFS), World Agroforestry (ICRAF), and its partners have been using Participatory Action Research (PAR) to fully engage key stakeholders in co-creating such CSA development strategies. This includes the testing of Agricultural Research for Development (AR4D) CSA scalability options. The multidisciplinary teams include the National Research and Extension Systems (NARES), national meteorological services (NMS), non-profit organizations (NGOs), and local radio programs, among others. The CCAFS-West Africa Program, World Agroforestry-West and Central Africa (ICRAF-WCA), International Union for Conservation of Nature (IUCN), University of Reading, and Centre Régional de Formation et d'Application en Agro-météorologie et Hydrologie Opérationnelle (AGRHYMET) provide technical backstopping to the national teams. Climate information (CI) was used as an entry point to inform the development of CSA technologies and practices within Climate-Smart Villages (CSV). This groundwork has led to a greater understanding of three critical factors for successful CSV implementation: (1) Building strong partnerships to co-design and develop agricultural systems that improve ecosystem and population resilience, (2) Key stakeholders (researchers, farmers, development agents, and students) capacity strengthening through vocational and academic training, and (3) Using CI for livelihood planning at all scales. These three factors support more effective identification and testing of agricultural technologies and practices addressing climate variability and change at plot, community, and landscape levels. This paper discusses the PAR-CSA methodology and parameters for evaluation, including biophysical and social change. Keys to success, including communication, knowledge sharing tools, and scalability are also discussed. Finally, future opportunities for improvement are presented, including knowledge product development, CSA policy and investment planning, capacity building, further engagement of the private sector, and additional research on existing practices and tools.

The article investigates the impact of aerosol composition on the estimation of the downwelling surface shortwave flux (DSSF). This initiative forms part of the efforts to improve the DSSF distributed by the Land Surface Analysis Satellite Application Facility (LSA-SAF). This operational product assumes invariant aerosol properties under clear sky conditions, which can be inaccurate for some regions of the world. This is the case of West Africa, where aerosol activity is not only highly variable due to frequent dust storms but also rich because of the coexistence of different aerosol species. This study was carried out over the West African stations of Dakar and Niamey, which represent different aerosol scenarios. Several dates during the dry season of 2006 were selected and classified into four different day types according to aerosol activity: standard, clean, mixture and dusty days. The diurnal evolution of DSSF and its direct and diffuse components were estimated for the selected dates by the current LSA-SAF algorithm and two other approaches using aerosol measurements from the Aerosol Robotic Network (AERONET) as input. The first alternative approach took the diurnal evolution of the total aerosol optical depth (AOD) into account, assuming a default desert aerosol type. Experiments with this method showed a significant improvement in the estimated DSSF compared to the current LSA-SAF algorithm. For example, root mean square error (RMSE) improved from 170 W/m2 to 50 W/m2 for dusty days in Dakar and from 73 W/m2 to 21 W/m2 for mixture days in Niamey. This improvement resulted from the consideration of a time-varying AOD, which accounted for the rapidly changing aerosol load for these two day types. The second alternative approach tested included consideration of the diurnal variation of the aerosol load and composition. Again, this was done using AERONET data on the fine and coarse aerosol modes, which may be associated with different sized dust particles, sea salt, or soot from biomass burning (depending on the date). This enhanced consideration of the aerosol composition greatly improved the estimation of the diffuse component of the DSSF, further reducing the RMSE during mixture days from 50 W/m2 to less than 10 W/m2. This improvement mainly came from consideration of the right scattering properties of the aerosol particles, which may be significantly different for each aerosol type.

La zone soudano-sahélienne de l'Afrique de l'Ouest a connu des sécheresses récurrentes depuis le milieu des années 1970 et aujourd'hui, on s'inquiète beaucoup de la façon dont cette région sera en mesure de s'adapter au changement climatique futur. Pour développer des stratégies d'adaptation bien ciblées, l'importance relative des facteurs climatiques en tant que moteurs de l'utilisation des terres et du changement des moyens de subsistance doit être mieux comprise. Sur la base des perceptions de 1 249 ménages dans cinq pays à travers un gradient annuel de précipitations de 400 à 900 mm, nous fournissons une estimation de la le poids des facteurs climatiques en tant que facteurs de changement dans les ménages ruraux au cours des 20 dernières années. Les facteurs climatiques, principalement des précipitations insuffisantes, sont perçus par 30 à 50 % des ménages comme une cause de diminution de la production de cultures pluviales, tandis qu'un large éventail d'autres facteurs explique les 50 à 70 % restants. Les facteurs climatiques sont beaucoup moins importants pour la diminution de la production animale et des zones de pâturage. L'augmentation des pâturages est également observée et causée par l'amélioration du régime foncier dans la zone la plus sèche. Les stratégies d'adaptation à la baisse de la production agricole comprennent la « prière » et la migration dans la zone de 400 à 500 mm ; le reboisement, la migration et le gouvernement soutien dans la zone 500-700 mm ; et amélioration des sols dans la zone 700-900 mm. Le déclin des exploitations d'élevage est contré par l'amélioration des ressources fourragères et des services vétérinaires. Il est conclu que, bien que la production de cultures pluviales soit principalement limitée par des facteurs climatiques, le bétail et les pâturages sont moins sensibles au climat dans toutes les zones de précipitations. Cela doit être reflété dans les stratégies nationales d'adaptation dans la région. La zona sudanosaheliana de África occidental ha experimentado sequías recurrentes desde mediados de la década de 1970 y hoy en día existe una preocupación considerable sobre cómo esta región podrá adaptarse al cambio climático futuro. Para desarrollar estrategias de adaptación bien dirigidas, es necesario comprender mejor la importancia relativa de los factores climáticos como impulsores del uso de la tierra y el cambio de los medios de vida. Sobre la base de las percepciones de 1249 hogares en cinco países con un gradiente de lluvia anual de 400-900 mm, proporcionamos una estimación de la el peso de los factores climáticos como impulsores de los cambios en los hogares rurales durante los últimos 20 años. Los factores climáticos, principalmente las precipitaciones inadecuadas, son percibidos por el 30-50% de los hogares como una causa de la disminución de la producción de cultivos de secano, mientras que una amplia gama de otros factores explica el 50-70% restante. Los factores climáticos son mucho menos importantes para la disminución de la producción ganadera y las áreas de pastoreo. Los aumentos en los pastos también se observan y son causados por la mejora de la tenencia en la zona más seca. Las estrategias de adaptación a la disminución de la producción de cultivos incluyen la "oración" y la migración en la zona de 400-500 mm; reforestación, migración y gobierno apoyo en la zona de 500-700 mm; y mejora del suelo en la zona de 700-900 mm. La disminución de las explotaciones ganaderas se contrarresta con la mejora de los recursos forrajeros y los servicios veterinarios. Se concluye que, aunque la producción de cultivos de secano está limitada principalmente por factores climáticos, el ganado y los pastos son menos sensibles al clima en todas las zonas de lluvia. Esto debe reflejarse en las estrategias nacionales de adaptación en la región. The Sudano-Sahelian zone of West Africa has experienced recurrent droughts since the mid-1970s and today there is considerable concern for how this region will be able to adapt to future climate change.To develop well targeted adaptation strategies, the relative importance of climate factors as drivers of land use and livelihood change need to be better understood.Based on the perceptions of 1249 households in five countries across an annual rainfall gradient of 400-900 mm, we provide an estimate of the relative weight of climate factors as drivers of changes in rural households during the past 20 years.Climate factors, mainly inadequate rainfall, are perceived by 30-50% of households to be a cause of decreasing rainfed crop production, whereas a wide range of other factors explains the remaining 50-70%.Climate factors are much less important for decreasing livestock production and pasture areas.Increases in pasture are also observed and caused by improved tenure in the driest zone.Adaptation strategies to declining crop production include 'prayer' and migration in the 400-500 mm zone; reforestation, migration, and government support in the 500-700 mm zone; and soil improvement in the 700-900 mm zone.Declining livestock holdings are countered by improved fodder resources and veterinary services.It is concluded that although rainfed crop production is mainly constrained by climate factors, livestock and pasture are less climate sensitive in all rainfall zones.This needs to be reflected in national adaptation strategies in the region. شهدت المنطقة السودانية الساحلية في غرب إفريقيا موجات جفاف متكررة منذ منتصف السبعينيات، واليوم هناك قلق كبير بشأن كيفية قدرة هذه المنطقة على التكيف مع تغير المناخ في المستقبل. لوضع استراتيجيات تكيف موجهة بشكل جيد، يجب فهم الأهمية النسبية للعوامل المناخية كمحركات لاستخدام الأراضي وتغير سبل العيش بشكل أفضل. بناءً على تصورات 1249 أسرة في خمسة بلدان عبر تدرج هطول الأمطار السنوي من 400-900 ملم، نقدم تقديرًا للنسبة وزن العوامل المناخية كمحركات للتغيرات في الأسر الريفية خلال السنوات العشرين الماضية. ينظر إلى العوامل المناخية، وخاصة عدم كفاية هطول الأمطار، من قبل 30-50 ٪ من الأسر على أنها سبب لانخفاض إنتاج المحاصيل البعلية، في حين أن مجموعة واسعة من العوامل الأخرى تفسر 50-70 ٪ المتبقية. العوامل المناخية أقل أهمية بكثير لانخفاض إنتاج الثروة الحيوانية ومناطق المراعي. كما لوحظت الزيادات في المراعي والناجمة عن تحسين الحيازة في المنطقة الأكثر جفافاً. تشمل استراتيجيات التكيف مع انخفاض إنتاج المحاصيل "الصلاة" والهجرة في منطقة 400-500 مم ؛ إعادة التشجير والهجرة والحكومة الدعم في منطقة 500-700 مم ؛ وتحسين التربة في منطقة 700-900 مم. يتم مواجهة انخفاض حيازات الماشية من خلال تحسين موارد الأعلاف والخدمات البيطرية. تم التوصل إلى أنه على الرغم من أن إنتاج المحاصيل البعلية مقيد بشكل أساسي بعوامل المناخ، إلا أن الثروة الحيوانية والمراعي أقل حساسية للمناخ في جميع مناطق هطول الأمطار. يجب أن ينعكس هذا في استراتيجيات التكيف الوطنية في المنطقة.

Climate variability has become a major issue for vital sectors in the context of climate change. In fisheries, in particular, the effects of climate change are reflected in the decline of fishing yield and loss of lives during extreme weather events in the sea. This study analyzed the perception of climate variability and change by fisher-folks, the attitude of fisher-folks toward the weather forecast and the adoption rate of the use of the weather forecast as well as the factors determining its use in Senegal. To this end, 576 fisher-folks belonging to 41 local fishing committees along the coastal areas were surveyed and focus group discussions were organized with key informants. The adoption rate was identified using the method of the average treatment effect (ATE) and the test of independency (chi-square) was used to analyze the perceptions of and beliefs on climate change. The results showed that 96% of fisher-folks perceive the change in the climate, though the effects are differently appreciated across the coastline. The most frequently observed effects are: coastal erosion, change in wind direction, increase in extreme swells and sea level rise. Nearly half of fisher-folks confirm that they noticed these changes over the past five years. In the Southern Coast in particular, 40% of fisher-folks stated that these changes happened 10 years ago. This statement is confirmed by the qualitative data. More than 90% of the respondents ascertain the weather forecast before going to fish, 63% regularly receive the weather forecast and 53% avoid going to sea during extreme events. In addition, the results showed that if the weather forecast was made accessible to the majority of fisher-folks, more than 83% would avoid going to sea during periods of extreme weather extreme events, thus reducing significantly the number of fatalities. The best way to protect the fisher-folks from the harmful effects of climate change is to ensure large-scale access to and use of accurate weather forecasts.

AbstractClimate adaptation is an essential strategy for responding to climate change at local levels and required for sustainable food production to meet the growing food demand. In this light, this study analyzed the effects of climate adaptation strategies on technical efficiency of maize farmers in Northern Ghana. This involved a total of 619 maize farmers that were selected through a multistage sampling procedure. A Cobb-Douglas stochastic frontier was fitted to the data. From the result, the major climate adaptation strategies adopted by the farmers include row planting, changing planting date, mixed farming, refilling, and intercropping. The frontier result shows that while climate adaptation significantly leads to higher maize outputs, only crop rotation and row planting significantly improve technical efficiency of maize farmers. Other factors that significantly influence maize output are farm size, labor, seed, and chemicals. The study concludes that climate adaptation, particularly, crop rotation and row planting, remains essential adaptation strategies for sustainable food production in the region. However, further understanding of mechanisms through which majority of the climate adaptation strategies significantly reduce technical efficiency is required.

According to existing literature, there are no conclusive results on the impact of stirring on hydrothermal carbonization (HTC); some studies report a significant impact on the product's properties, while others indicate no influence. This study investigates the influence of stirring rate on several responses and properties of HTC products, including solid mass yield, solid carbon fraction, surface area, surface functional groups, morphology, and the fate of inorganic elements during HTC. Waste biomass was introduced as a feedstock to a 2 L HTC reactor, where the effects of temperature (180-250 °C), residence time (4-12 h), biomass to water (B/W) ratio (1-10%), and stirring rate (0-130 rpm) were investigated. The findings of this study conclusively indicated that the stirring rate does not influence any of the studied responses or properties of hydrochar under the selected experimental conditions used in this study. Nevertheless, the results indicated that a low-stirring rate (5 RPM) is enough to slightly enhanced the heating-up phase of the HTC reactor. For future research, it is recommended to examine the impact of stirring rate on the HTC of other types of biomass using the methodology developed in this study.