Impact of human-induced desertification on the intensification of Sahel dust emission and export over the last decades

摘要

Human-induced soil degradation in Sahel is a major concern for regional climate change. A significant increase in long-range atmospheric dust transport due to human activities would indeed modify the radiative budget and the water cycle over both Africa and the tropical Atlantic. Here we use two independent long-term datasets, i.e., surface concentration measurements at Barbados between 1965 and 2000 and maps of TOMS dust optical thickness between 1979 and 2000, to evidence an increase of a factor of two of background dust loads over the Atlantic since the mid 60' s, independently of any climatic phenomenon. Satellite imagery suggests that this trend can be attributed to an intensification of dust emissions in a Sahel region centered on southern Mali. The desertification caused by the doubling of the population in Sahel over the last 40 years likely explains the observed intensification of the Atlantic dust export.