Abstract. Projections of the response of Sahel rainfall to future global warming diverge significantly. Meanwhile, paleoclimatic records suggest that Sahel rainfall is capable of abrupt transitions in response to gradual forcing. Here we present climate modeling evidence for the possibility of an abrupt intensification of Sahel rainfall under future climate change. Analyzing 30 coupled global c...

West Africa includes a semi-arid zone between the Sahara Desert and the humid Gulf of Guinea coast, approximately between 10°N and 20°N, which is irrigated by summer monsoon rains. This article refers to the region as the Sahel. Rain-fed agriculture is the primary sustenance for Sahel populations, and severe droughts (in the 1970s and 1980s), therefore, have devastating negative societal impact...

[1] Recurrence times for extreme drought events in the African Sahel are estimated using a classical peaks-overthreshold model. Results, which are computed for both mean seasonal rainfall and fractional area in drought, suggest that the distribution of dry extremes after about 1970 is statistically distinct from that of preceding years. This finding throws into relief the critical role played b...

Some drought years over sub-Saharan west Africa (1972, 1977, 1984) have been previously related to a cross-equatorial Atlantic gradient pattern with anomalously warm sea surface temperatures (SSTs) south of 10 N and anomalously cold SSTs north of 10 N. This SST dipolelike pattern was not characteristic of 1983, the third driest summer of the twentieth century in the Sahel. This study presents e...

[1] In order to investigate a possible link between tropical Northeast (NE) Atlantic sea-surface temperature (SST), Atlantic meridional overturning circulation (AMOC), and drought in the Sahel during the past 44 thousand years (kyr) we used alkenone paleothermometry and dC of C. wuellerstorfi of a marine sediment core from the continental slope off Senegal. Our data show periods of low SST and ...

The outlook for Sahel precipitation in coupled simulations of the 21 century is very uncertain, with different models disagreeing even on the sign of the trends. Such disagreement is especially surprising in light of the robust response of the same coupled models to the 20 century forcings. We present a statistical analysis of the pre-industrial, 20 century and 21 century A1B scenario simulatio...

Parts of Africa have the most rapid population growth in the world. Recent studies by climatologists suggest that, in coming decades, ecologically vulnerable areas of Africa, including the Sahel will be exposed to the harshest adverse effects of global warming. The threat hanging over parts of sub-Saharan Africa is extreme. Fortunately, there are evidence-based achievable policies which can gre...

The outlook for Sahel precipitation in coupled simulations of the twenty-first century is very uncertain, with different models disagreeing even on the sign of the trends. Such disagreement is especially surprising in light of the robust response of the same coupled models to the twentieth-century forcings. This study presents a statistical analysis of the preindustrial, twentieth-century and t...

Water evaporating from the ocean sustains precipitation on land. This ocean-to-land moisture transport leaves an imprint on sea surface salinity (SSS). Thus, the question arises of whether variations in SSS can provide insight into terrestrial precipitation. This study provides evidence that springtime SSS in the subtropical North Atlantic ocean can be used as a predictor of terrestrial precipi...

The impact of the increase of greenhouse gases on Sahelian precipitation is very uncertain in both its spatial pattern and magnitude. In particular, the relative importance of internal variability versus external forcings depends on the time horizon considered in the climate projection. In this study we address the respective roles of the internal climate variability versus external forcings on...