Volume 2, Number 6: 15 March 1999
During the 1970s, the United Nations spearheaded a massive international media campaign to warn the world about the occurrence of extreme and widespread desertification in the African Sahel. Expanding deserts and prolonged droughts were two phrases commonly used in conjunction with video footage showing blowing desert sands or dried mud-caked reservoirs that once held water. After viewing numerous such images on television sets across the globe, the general public readily accepted the United Nations' claim that desertification was an escalating environmental threat that needed to be confronted. And in the wake of growing public concern, the UN was able to convince many nations to follow its prescriptions for a cure. But were they right? Was the African Sahel really "headed for hell in a handbasket"?
Recently, two papers were published that studied the degree of desertification in the African Sahel for two overlapping time periods; and what they report should be viewed as a wake-up call to our global citizenry. In the first paper, Nicholson et al. (1998) used satellite images of the Central and Western Sahel from 1980 to 1995 to determine the extent of desertification in this region. 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. They reported finding no overall expansion of deserts during their 16-year study, and no decrease in RUE, although vegetation did expand and contract in response to periods of rainfall and drought. Hence, neither human activities nor climatic conditions in this arid region caused massive desertification of the type that was highly publicized by the United Nations in the 1970s.
In the second study, Prince et al. (1998) also used satellite images and RUE to map the occurrence and severity of desertification, but they did so for the entire Sahel from 1982 to 1990. They too indicated the absence of widespread desertification and determined that RUE did not decline during their 9-year investigation. In fact, they discovered a small but steady rise in RUE for the Sahel as a whole, suggesting that plant productivity there had increased over the time of their study. Although the authors mentioned several factors that might have contributed to this increase, they overlooked the one factor that may have had the greatest influence of all --the aerial fertilization effect of the ongoing rise in the air's CO2 content that greatly enhances plant water-use efficiency and enables plants to grow in areas that once were too dry to sustain them.
As human beings we strive to learn from our errors, lest we foolishly make the same mistakes; and in this day of another UN-inspired campaign (designed to convince us of the reality of CO2-induced global warming), we should remember how the United Nations "cried wolf" with respect to their claim of escalating desertification in Africa. They were clearly wrong before, and they can clearly be wrong again. In fact, they could well be doubly wrong; for not only is there no compelling reason to believe that rising atmospheric CO2 levels must necessarily warm the earth, there are many reasons to believe that it is actually helping the biosphere, as in the slight "greening of the Sahel" suggested by the increasing RUE discovered by Prince et al.
The bottom line? Don't swallow the medicine if you're not sick!
| Dr. Craig D. Idso President |
Dr. Keith E. Idso Vice President |
References Nicholson, S.E., Tucker, C.J. and Ba, M.B. 1998. Desertification, drought, and surface vegetation: An example from the West African Sahel. Bulletin of the American Meteorological Society 79: 815-829. |