The Palmer Drought Severity Index (PDSI) was calculated globally using gridded monthly air temperature and precipitation. From 1900 to 1995, there are large multiyear to decadal variations in the percentage areas in severe drought (PDSI < −3.0) and severe moisture surplus (PDSI > +3.0) over many land areas while secular trends are small. Since the late 1970s, however, there have been some incre...

In the West African Sahel, the majority of the population depends on subsistence farming and livestock breeding and is thus particularly vulnerable to climatic changes. One possible response to natural hazards is migration. Recent research suggests that environmentally induced mobility is closely linked to the social vulnerability and adaptive capacity of individuals and groups. However, only l...

BACKGROUND The Sahel region of West Africa has the highest bacterial meningitis attack and case fatality rate in the world. The effect of climatic factors on patterns of invasive respiratory bacterial disease is not well documented. OBJECTIVE We aimed to assess the link between climatic factors and occurrence of invasive respiratory bacterial disease in a Sahel region of Niger. METHODS We c...

Water loss is a crucial factor for vegetation in the semi-arid Sahel region of Africa. Global satellite-driven estimates of plant CO2 uptake (gross primary productivity, GPP) have been found to not accurately account for Sahelian conditions, particularly the impact of canopy water stress. Here, we identify the main biophysical limitations that induce canopy water stress in Sahelian vegetation a...

In the Sudano-Sahelian areas of Africa droughts can have serious impacts on natural resources, and therefore land surface moisture is an important factor. Insufficient conventional sites for monitoring land surface moisture make the use of Earth Observation data for this purpose a key issue. In this study we explored the potential of using reflectance data in the Red, Near Infrared (NIR), and S...

The assessment of land degradation and the quantification of its effects on land productivity have been both a scientific and political challenge. After four decades of Earth Observation (EO) applications, little agreement has been gained on the magnitude and direction of land degradation in the Sahel. The large number of EO datasets and methods associated with the complex interactions among bi...

A populational study of the compatibility between Schistosoma haematobium and its potential vectors has been carried out in the Niger, confronting samples of S. haematobium populations from three epidemiologic foci with Bulinus populations originating from the same focus (sympatric infection) and with Bulinus populations from other foci (allopatric infections). The three transmission foci selec...

Within the framework of the capacity-building project for better integration of nutrition and food security programming1, FAO has asked humanitarian organizations in Western Africa and the Sahel (Chad, Burkina Faso, Niger and Mali) and in the Horn of Africa (Kenya, Somalia, South Sudan and Ethiopia) to share their experiences and lessons learnt on implementing integrated programmes, and more pa...

[1] Since the 1980s, a dramatic downward trend in North African dustiness and transport to the tropical Atlantic Ocean has been observed by different data sets and methods. The precise causes of this trend have previously been difficult to understand, partly due to the sparse observational record. Here we show that a decrease in surface wind speeds associated with increased roughness due to mor...

Synoptic-scale African easterly waves (AEWs) impact weather throughout the greater Atlantic basin. Over the African continent, AEWs are instrumental in initiating and organizing precipitation in the drought-vulnerable Sahel region. AEWs also serve as the precursors to the most intense Atlantic hurricanes, and contribute to the global transport of Saharan dust. Given the relevance of AEWs for th...