Greener Southern Sahara: An Enhanced Carbon Sink

In this study, we examine the precipitation, vegetation index, photosynthesis, net ecosystem exchange (NEE), atmospheric CO 2 concentrations, and horizontal and vertical transports over the Sahara Desert. The precipitation during August–October is over 17 times higher than in January–March, which is driven by Intertropical Convergence Zone migration, stronger African Monsoon, and increased rising motion over the Sahara. Photosynthetic activity, monitored by Solar‐Induced Fluorescence (SIF), is twice as high in August–October than in January–March, highlighting the impact of rainfall on the plant's growth. Increased photosynthetic activities (high SIF) and enhanced CO 2 uptake by the biosphere (negative NEE) will remove more CO 2 from the atmosphere, resulting in atmospheric CO 2 levels being ∼4 ppm lower during August–October than January–March. Lower CO 2 levels in August–October are also captured by the CarbonTracker model. We further analyze correlations among detrended timeseries of one‐month‐lead precipitation, normalized difference vegetation index, and NEE averaged over the Sahara Desert during the wet season. The results show significant correlations, with higher precipitation associated with increased vegetation coverage and stronger CO 2 uptake. A long‐term analysis reveals increasing trends in both precipitation and vegetation index and a decreasing trend in NEE during the wet season. These findings suggest that the Sahara Desert is becoming greener and evolving into a stronger carbon sink, as increased vegetation absorbing more CO 2 from the atmosphere.