Desertification, Drought, and Surface Vegetation: An Example from the West African Sahel

TLDR

Desertification in West Africa has long been assumed to be an advancing, irreversible anthropogenic process linked to higher albedo, dust generation, and reduced land productivity. The study examines the history and meteorological aspects of desertification in West Africa and presents analyses addressing this issue. The authors review historical data and conduct selected analyses of meteorological factors to assess desertification. The study finds no progressive change in the Saharan boundary or Sahel vegetation cover over the past 16 years, nor a systematic decline in vegetation water‑use efficiency, though a modest albedo change of up to 0.10 % since the 1950s is possible.

Abstract

Many assumptions have been made about the nature and character of desertification in West Africa. This paper examines the history of this issue, reviews the current state of our knowledge concerning the meteorological aspects of desertification, and presents the results of a select group of analyses related to this question. The common notion of desertification is of an advancing “desert,” a generally irreversible anthropogenic process. This process has been linked to increased surface albedo, increased dust generation, and reduced productivity of the land. This study demonstrates that there has been no progressive change of either the Saharan boundary or vegetation cover in the Sahel during the last 16 years, nor has there been a systematic reduction of “productivity” as assessed by the water-use efficiency of the vegetation cover. While it also showed little change in surface albedo during the years analyzed, this study suggests that a change in albedo of up to 0.10% since the 1950s is conceivable.