Abstract:
In this study, we investigate changes in temperature and precipitation extremes over West and Central
Africa (hereafter,WAF domain) as a function of global mean temperature with a focus on the
implications of global warming of 1.5 ◦C and 2◦C according the Paris Agreement. We applied a
scaling approach to capture changes in climate extremes with increase in global mean temperature in
several subregions within the WAF domain: Western Sahel, Central Sahel, Eastern Sahel, Guinea
Coast and Central Africa including Congo Basin.
While there are several uncertainties and large ensemble spread in the projections of temperature
and precipitation indices, most models show high-impact changes in climate extremes at subregional
scale. At these smaller scales, temperature increases within theWAF domain are projected to be
higher than the global mean temperature increase (at 1.5 ◦C and at 2◦C) and heat waves are expected
to be more frequent and of longer duration. The most intense warming is observed over the drier
regions of the Sahel, in the central Sahel and particularly in the eastern Sahel, where the precipitation
and the soil moisture anomalies have the highest probability of projected increase at a global warming
of 1.5 ◦C. Over the wetter regions of the Guinea Coast and Central Africa, models project a weak
change in total precipitation and a decrease of the length of wet spells, while these two regions have
the highest increase of heavy rainfall in the WAF domain at a global warming of 1.5 ◦C. Western Sahel
is projected by 80% of the models to experience the strongest drying with a significant increase in the
length of dry spells and a decrease in the standardized precipitation evapotranspiration index. This
study suggests that the ‘dry gets drier, wet gets wetter’ paradigm is not valid within theWAF domain.
