What was done
The authors used satellite images of the Central and Western Sahel from 1980 to 1995 to determine if severe and extensive desertification had occurred in this region over this time period.  In addition, rain-use efficiency (RUE), which relates plant productivity to rainfall, was calculated to determine if biological productivity in the area was affected by factors other than drought.

What was learned
The data revealed no overall expansion of deserts in the Central and Western Sahel during the 16-year study, although vegetation did expand and contract in response to periods of rainfall and drought.  Hence, neither human activities nor climatic conditions in the Central and Western Sahel resulted in massive desertification of the type that was highly publicized by the United Nations in the 1970's.

What it means
The lack of a decline in RUE for the Central and Western Sahel between 1980 and 1995, in conjunction with vegetative indices developed from satellite images, indicate that no extensive land degradation, desertification, or reduction in plant productivity occurred in this region during this time frame.  As the CO2 content of the air continues to rise, it is likely that researchers will be able to use these data as a baseline from which future increases in plant productivity and water-use efficiency (which are common phenomena associated with elevated CO2 levels) may be chronicled within this arid portion of the West African Sahel.