Multi-model trends in the Sahara induced by increasing CO₂

Five of eighteen climate system models participating the Coupled Model Intercomparison Project (CMIP) are chosen here for analysis based on their ability to simulate a reasonable present-day climatology of the Sahara Desert with similar rainfall distributions and meridional boundaries as in the observational data. When CO₂ concentration is increased at one percent per year for 80 years in these models the Sahara moves north, becomes hotter and dries. Compared to the 40-year control run climatology, the mean average northward shift is around 0.55° latitude and the surface temperature is about 1.8°C warmer at year 70 when the CO₂ doubles. The local enhanced greenhouse effect from increased CO₂ increases the net surface sensible heat flux, which in turn contributes to the warming trend.