Small, J., Goetz, S.J. and Hay, S.I. 2003. Climatic suitability for malaria transmission in Africa, 1911-1995. Proceedings of the National Academy of Sciences USA 100: 15,341-15,345.
What was done
The authors examined trends in a climate-driven model of malaria transmission for the African continent between 1911 and 1995, using a spatially and temporally extensive gridded climate data-set to identify locations where the malaria transmission climate suitability index changed significantly over this time interval. Then, after determining areas of change, they more closely examined the underlying climate forcing of malaria transmission suitability for those localities.
What was learned
It was determined that malaria transmission suitability did indeed increase because of climate change in specific locations of limited extent; but in Southern Mozambique, which was the only region for which climatic suitability consistently increased, the cause of the increase was increased precipitation, while areas where the climate became less suitable for malaria transmission had all experienced decreased rainfall. In fact, Small et al. say that "climate warming, expressed as a systematic temperature increase over the 85-year period, does not appear to be responsible for an increase in malaria suitability over any [our italics] region in Africa."
What it means
Contrary to the doom and gloom scenarios peddled by climate alarmists intent on destroying the fossil fuel industry that undergirds the global economy, this study suggests we have little-to-nothing to fear about global warming in terms of enhanced malaria transmission. This would also appear to be the thinking of Small et al., who conclude that "research on the links between climate change and the recent resurgence of malaria across Africa would be best served through refinements in maps and models of precipitation patterns and through closer examination of the role of nonclimatic influences," the great significance of which has recently been demonstrated by Reiter et al. (2003) for dengue fever, another important mosquito-borne disease.
Reiter, P., Lathrop, S., Bunning, M., Biggerstaff, B., Singer, D., Tiwari, T., Baber, L., Amador, M., Thirion, J., Hayes, J., Seca, C., Mendez, J., Ramirez, B., Robinson, J., Rawlings, J., Vorndam, V., Waterman, S., Gubier, D., Clark, G. and Hayes, E. 2003. Texas lifestyle limits transmission of Dengue virus. Emerging Infectious Diseases 9: 86-89.
Reviewed 31 March 2004