3b. Biophysical Causes of Desertification: SSTs


    Evidence of global climate change is abundant; however, evidence to the correlation between Sea Surface Temperatures (SSTs) and rainfall variability in the Sahel as a causation of desertification is at the forefront of climate change models. Experts in the field such as create models to help better forecast the effect of climate change on rainfall which in turns affects desertiification.  One such model is that of Dr. Isaac M. Held, Senior Research Scientist for Geophysical Fluid Dynamics Laboratory (GFDL) and National Oceanic and Atmosphere administration (NOAA) and Princeton University professor in the Geosciences. 

    In Dr. Held’s, et. al Simulation of Sahel drought in the 20th and 21st centuries (2005), he uses “global climate model (CM2) that generates a simulation of the 20th century rainfall record in the Sahel generally consistent with observations” (Held, et al. 2005).  The model suggests that there has been an “anthropogenic drying trend in this region, due partly to increased aerosol loading and partly to increased greenhouse gases, and that the observed 20th century record is a superposition of this drying trend and large internal variability” (Held, et al. 2005).

    In addition, Dr. Held’s, et al. models provide evidence that Sea Surface Temperature warming, through increase in global warming due to greenhouse gases, affects rainfall variability in the Sahel thus making it a biophysical factor for desertification reinforced and accelerated through human activity. In his own words, and through scientific climate modeling, Dr. Held contends that the models in Simulation of Sahel drought in the 20th and 21st centuries (2005), “provide our best evidence to date that a model that does dry the Sahel strongly in response to uniform warming can be broadly consistent with the 20th century record.”

    Dr. held concludes with reputable evidence and significant scientific scrutiny and collaboration that “it has become clear from atmospheric modeling and observational analyses begun in the 1980s that many aspects of Sahel rainfall variability are, in fact, controlled by sea surface temperatures (SSTs) ” (Held, et al. 2005).





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