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

 | 
Benjamin Sultan
, 
Richard Lalou
, 
Mouftaou Amadou Sanni
, 
et al.

Table des matières

Benjamin Sultan, Richard Lalou, Amadou Oumarou et al.

Introduction

A close link between climate and agricultural production
The need for an interdisciplinary approach
The Escape Project
Description of the book
1. Recent and future climate changes in West Africa: the obvious, the uncertain and the perceived
2. Environmental changes and the impacts of the climate
3. Societal changes of rural populations
4. Adaptations to farming systems, innovations

Part I. Recent and future climate change in West Africa. Obvious features, uncertainties and perceptions

Théo Vischel

Introduction

Françoise Guichard, Laurent Kergoat, Frédéric Hourdin et al.

Chapter 1. Climate warming observed in the Sahel since 1950

Introduction
Strong multidecadal warming with contrasts according to the season
The Sahelian climate: temperature, humidity and monsoon rainfall
The annual cycle of the warming observed during the last 60-year period
The evolution of minimum and maximum daily temperatures
The importance of the differences between diurnal and nocturnal temperature
Distinct annual cycles of Tmin and Tmax
Focus on the spring
Meridional gradient
Repercussions on the spring trends
What can be expected from meteorological reanalyses?
How do climate models simulate the warming observed?
Conclusion
Théo Vischel, Thierry Lebel, Gérémy Panthou et al.

Chapter 2. The return of a wet period in the Sahel?

Observations and prospects

Introduction
The return of rainfall in the Sahel: regional disparities at the annual scale
Review of recent decadal variability
Variability of characteristics of the season
The recovery of rainfall in the Sahel: a question of scale
Mesoscale convective systems: a key scale in the link between climate and impact
The impact of mesoscale rainfall on the notion of dry year and wet year
Rainfall evolution at the scale of hydrological and agronomic impacts
Evolution of the characteristics of mesoscale convective systems since 1950
Evolution of the extreme precipitation regime
Summary, discussion and questions still unanswered
Abdoulaye Deme, Amadou Thierno Gaye et Frédéric Hourdin

Chapter 3. Climate projections in West Africa: the obvious and the uncertain

Introduction
Data and methods
CMIP5 simulations
Reanalysis and observations
The representation of several features of the WAM in the CMIP5 models
The seasonal cycle of the WAM
Onset of the monsoon
What are the climate projections for West Africa in the 21st century?
Rainfall projections for West Africa in the 21st century
Temperature projections for West Africa in the 21st century
What are the obvious features and uncertainties of climate projections for the 21st century in West Africa?
Precipitation
Temperatures
Conclusion
Frédéric Kosmowski, Richard Lalou, Benjamin Sultan et al.

Chapter 4. Contrasting perceptions with climate change

Scientific observations in three West African contexts

Introduction
The context of the research
Material and methods
Climate change in the region
How do the populations perceive these changes?
Does everybody perceive the climate in the same way?
Conclusion
Anne Attané, Amadou Oumarou et Mame Arame Soumaré

Chapter 5. When nature talks to us

Comparative analysis of representations of climatic and environmental changes

Introduction
The issue of translation, a challenge for anthropology?
Continuities: the transmission of knowledge about meteorological forecasting
Changes observed in climate features: rain, temperature and wind
Disturbances of rainy seasons
Changes of temperature
Changes in wind characteristics
Breaks: between the disappearance of ‘known phenomena’ …
… and the appearance of ‘new phenomena’
The causality of changes in the climate and the environment
Anthropic causes
Causes associated with sociocultural representations
Interpretation by marabouts, Islamic scholars
Rites practiced by zimmas, the holders of local animist beliefs
In conclusion

Part II. Impacts of the climate and environmental changes

Laurent Kergoat

Introduction

Cécile Dardel, Laurent Kergoat, Pierre Hiernaux et al.

Chapter 6. Between desertification and regreening of the Sahel

What is really happening?

Introduction
‘Regreening’, a term dating back to the first satellite analyses
Comparison with in situ measurement networks (Mali, Niger)
The Gourma in Mali
The case of Fakara in Niger
Can these trends be explained by the evolution of rainfall?
The Gourma, Mali
The case of the Fakara in Niger
Simulation of herbaceous plant production in the Gourma during the period 1950-2012
What is the future for Sahelian systems?
Luc Descroix, Gil Mahé, Jean-claude Olivry et al.

Chapter 7. Anthropic and environmental factors involved in the increase in flooding in the Sahel

Introduction
An increase in flows that has led to increased risks of flooding
A climatic factor: the increase in the number of rainfall events with high cumulated depths
An ‘urban’ explanation
Impermeabilisation of urban and peri-urban zones
The urbanisation of areas with a flood risk
An acceleration of hydrologic and sedimentary processes
The silting up of riverbeds (the case of the River Niger)
Increased exorheism
Conclusion
Acknowledgements
Pierre Hiernaux, Mamadou Oumar Diawara, Laurent Kergoat et al.

Chapter 8. The forage constraint in pastoral and agropastoral livestock farming in the Sahel

Adaptation and prospects

Introduction: the forage question
The diversity and interrelations of livestock systems in the Sahel
Forage balances
Estimate of the forage resources of the land in the commune of Hombori and nearby areas
Estimate of available forage in the areas of 14 villages in the commune of Dantiandou
The forage balance in the commune of Hombori
Forage balance at Dantiandou
Comparison of the forage balances drawn up for Hombori and Dantiandou
Forage balances and livestock productivity
Conclusion: prospects for the development of livestock farming in the Sahel
Acknowledgements
Laurent Kergoat, Manuela Grippa, Pierre Hiernaux et al.

Chapter 9. Paradoxical pond changes in the non-cultivated Sahel

Diagnosis, causes and consequences

Introduction
‘The rains decrease and the ponds rise’: ponds in the Gourma (1950 to 2010)
The example of Agoufou and Ebang Mallam ponds
Looking at the whole Gourma
Can an intensification of precipitation be excluded?
The Tin Adjar drainage basin (Mali)
A regional phenomenon?
Possible mechanisms
Changing ecohydrology
Are degradation and regreening compatible?
Consequences of this environmental change
Conclusions
Benjamin Sultan, Philippe Roudier et Seydou Traoré

Chapter 10. The impacts of climate change on crop yields in West Africa

Introduction
Drafting future yield scenarios
Generating the future climate
Crop modelling
Linking GCMs and cropping models
Adaptation to climate change
A decrease in agricultural yields under the effect of climate change
The respective influence of changes in temperatures and precipitation in yield scenarios
A contrast between the western and central Sahel in the yield scenarios
Conclusions

Part III. Social changes in rural populations

Bénédicte Gastineau

Introduction

Bénédicte Gastineau, Moustapha Gibigaye, Frédéric Kosmowski et al.

Chapter 11. Rural populations faced with environmental hazards

African experiences

The environment and adaptation of rural populations in Africa
Matching the management of environmental resources and forms of social and family organisation
Adaptation: an old, ceaselessly renewed feature
Adaptation: what to and how?
Strategies for forcing up to environmental events (Djougou local authority area)
Results
Large households but a fairly small reserve of labour
Food security of the household is a priority
The diversification of income: a necessary strategy that must not compete with agricultural work
Effective adaptation strategies?
Conclusion
Fabrice Gangneron et Élodie Robert

Chapter 12. Land rights and fertility management

Two different perspectives: Djougou (Benin) and Niakhar (Senegal)

Introduction
Administrative rights and rights of use
Djougou
Niakhar
Maintening soil fertility
Djougou
Niakhar
Dynamics compared
Permanent features
Continuity
Discontinuity
Boserup’s analysis
What are the future prospects?
Fertility, techniques and labour
Land
Conclusion
Alain Bonnassieux et Fabrice Gangneron

Chapter 13. The role of seasonal and pluri-annual migration in reducing vulnerability

Hombori and Djougou districts

Climatic and environmental crises and migration: divergent positions
Hombori, a dominantly pastoral district where migration goes back a long way
Before 1970, migration to coastal countries had composite purposes
Migrations during the 1970s and 1980s crises
Profiles of today’s migrants and the reasons for migration
Migrations in an area with smaller potential
Migration systems based on contacts
Processes of individual affirmation and the diversification of work
Djougou: diversified farm production but precarious groups in a position of inferiority
Semi-captive labour on farms in Nigeria
Forms of capitalisation for returning home: a motorcycle and knowledge
Female migrations for domestic service or work in informal micro-enterprises
Differences and similarities between temporary migration in Hombori and Djougou
Richard Lalou et Valérie Delaunay

Chapter 14. Seasonal migration and climate change in rural Senegal

A form of adaptation or failure to adapt?

Introduction
Context of the study
Material and methods
Definitions and measurements of migration
Farm classification method
Population movements dominated by seasonal migration
Long-term migration
Seasonal labour migration
Seasonal migrations, climatic factors and food security
Conclusion
Amadou Oumarou

Chapter 15. Female migration, a non-farming strategy for adaptation to climatic and environmental changes in the Imanan (Niger)

Introduction
The district of Imanan, a framework for the analysis of female migration in Niger
Female migration, a relevant subject for study in the district of Imanan
Female migration, a growing practice in the Imanan
The new form of female mobility: many reasons
Dwindling agricultural production
Sociocultural category as a factor in the likelihood of female mobility
Matrimonial status and age as potential factors in migration
Social networks, an incitement for migration
An ambivalent phenomenom
A factor in the increased autonomy of women?
More visible participation of women in covering the food requirements of the household
More marked economic independence of girls
A new appearance or ‘look’ for migrants
A perversion of social values in the Imanan
Conclusion
Abdoulaye Mohamadou et Harouna Abdoutan

Chapter 16. Political changes, landholding dynamics and socio-economic reconstruction

Imanan administrative district (Niger)

Introduction
Imanan administrative area: a nomadic/pastoral area in an agricultural zone
Mobility and sedentariness in an area undergoing degradation
The conquest of the area by the Tuaregs
The re-drawing of the boundaries by the colonial administration
The release of slaves and new procedures for access to land
From grouped to scattered settlements
The return to valley land: the development of market garden crops
The district land commission as an institutional innovation
Dependents: from economic autonomy to political representation
Conclusion

Part IV. Adaptation of farming systems, innovations

Richard Lalou

Introduction

Frédéric Kosmowski, Moustapha Gibigaye, Bertrand Muller et al.

Chapter 17. Innovation in rural West Africa

What changes in farming practices?

Introduction
Method
Context
Changes in farming practices
Tree planting
Changes in sowing dates
Introduction of new crop associations
The introduction of new crops: soya
Introduction of new maize and yam varieties
Conclusion
Acknowledgements
Bertrand Muller, Richard Lalou, Patrice Kouakou et al.

Chapter 18. The return of Sanio millet in the Sine

Rational adaptation to climate evolution

Introduction
An agropastoral region with climatic and demographic constraints
Material and methods
Study of the climate determinant in the return of Sanio
Analysis of the social, economic and cultural factors associated with the return of Sanio
Cartography of the present cultivation of Sanio and its spread
A crop that is possible again but still risky
A crop whose qualities are appreciated and that is easy to grow but of no monetary interest
Continued Sanio cultivation areas from which seed has been distributed for 10 years
The recovery of rainfall: a necessary condition but not enough for the recovery of Sanio
Conclusion: adaptation to climatic evolution whose future remains uncertain
Acknowledgements
Élise Audouin, Jonathan Vayssières, Mariana Odru et al.

Chapter 19. Reintroducing livestock to increase the sustainability of village landscapes in West Africa

The case of groundnut basin in Senegal

Introduction
Material and method
The conceptual model guiding analysis
The system studied: the village terroir
Household and field units
Data gathering and field units
Household surveys
Biomass flow database
Spatialisation of flows and stocks using a geographic information system
Calculated sustainability indicators
Results
Village structure
Dwelling and land use
Human and animal populations, land available and rotations
Diversity of households
Farming practices and equipments
The hinging of livestocks and crop farming
Fertilisation of cultivated land
Crop management and yields
Sustainability indicators
At field level
At household level
At terroir level
General discussion: the effects of fattening on the sustainability of terroirs in West Africa
Conclusion
Acknowledgements
Ramatou Hassane

Chapter 20. An example of adaptative strategy in the face of food insecurity

Potato growing in the Imanan (Niger-republic)

Introduction
Methodological procedure
Context of the study
Worsening of the climate, a limit to rainfed agriculture
Potato yielding as a dominant adaptive strategy
Factors involved in the diffusion of potato growing
Internal factors
External factors
The improvement of the well-being of the population in the potato’s farming
The funding mechanisms of potato production
Confidence, a necessary condition for loans from Maï Gida
The informal funding practices of the Maï Gida
Behaviour and strategies of growers and traders
Conclusion
Benjamin Sultan, Richard Lalou, Mouftaou Amadou Sanni et al.

Conclusion

New environmental opportunities
Perceptions that tend to correspond to the ongoing changes
Cultural and adaptive innovations
Migration: one component of a self-adaptive system
New climate risks
Lasting constraints and vulnerabilities
Environmental changes and adaptation strategies analysed at the local scale
The advantage of the interdisciplinary approach and observations over long periods
Research to be carried out on anticipatory adaptation
 
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