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Malaria in a Warmer World: Rational Projections
Volume 3, Number 24: 27 September 2000

In a recent research report in Science, Rogers and Randolph (2000) note what is probably well known to all, namely, that "predictions of global climate change have stimulated forecasts that vector-borne diseases will spread into regions that are at present too cool for their persistence."  In fact, these predictions comprise one of the major scare-stories that climate alarmists use to demonize society's CO2-emitting activities.   "To capture the public's imagination," as Stephen Schneider once stated (Discover Magazine, October 1989), "we have to offer up scary scenarios, make simplified dramatic statements, and make little mention of any doubts we might have" in order to get broad-based support for anti-CO2 proposals such as the Kyoto protocol.   This unsolicited confession from one of the world's major proponents of CO2 emissions regulations suggests to us that whenever one hears such "scary and dramatic statements," one ought be more than a little suspicious about them.  And the results of the Rogers and Randolph study only confirm our thoughts on the subject.

Nearly all of the doom-and-gloom reports of global warming effects on malaria have typically used only one, or at most two, climate variables to make predictions of the future distribution of this disease over the earth.  The study of Rogers and Randolph, however, employed five.   Briefly, they used the present-day distribution of malaria to determine the specific climatic constraints that best define that distribution, after which the multivariate relationship they derived from this exercise was applied to future climate scenarios derived from state-of-the-art general circulation models of the atmosphere.

So what was found?  In the words of Dye and Reiter (2000), who were invited to produce a Perspective piece on the Rogers and Randolph report, the new approach produces a "substantially better" fit to current malaria incidence data than any previous model.  And what does their approach to the problem predict about the future?  Very little change: a 0.84% increase in exposure potential under the "medium-high" scenario of global warming produced by the HadCM2 model of the UK's Hadley Centre for Climate Prediction and Research and a 0.92% decrease under the HadCM2 "high" scenario.

In commenting on this result, Rogers and Randolph explicitly state that their quantitative model "contradicts prevailing forecasts of global malaria expansion" and that "it highlights the use [we would say superiority] of multivariate rather than univariate constraints in such applications and the advantage of statistical rather than biological approaches in situations where biological knowledge is incomplete."

Clearly, this important new study totally demolishes previous claims that any future global warming will allow malaria to spread into currently malaria-free regions of the world.  What is more, Dye and Reiter say that the new results "lead us to question whether other climate-related health warnings - for asthma, cholera epidemics, or heat-induced deaths, for example - would stand up to a more sophisticated multivariate analysis."

In spite of this very good news, there is an even more powerful reason to reject the old horror stories of diseases run rampant as a result of possible global warming; and that is human intervention.  In the words of Dye and Reiter, "given adequate funding, technology, and, above all, commitment, the campaign to 'Roll Back Malaria,' spearheaded by the World Health Organization, will have halved deaths related to [malaria] by 2010," so that "by 2050, the map of malaria distribution should bear little resemblance to the one drawn by Rogers and Randolph."  In fact, if all goes well, there may not even be such a map.

Yes, as standards of living rise and people can commit more resources to basic public health programs, many diseases that now take a terrible toll on humanity will indeed be drastically reduced.  To continue to predict the opposite, as climate alarmists are wont to do, is truly unconscionable, as are the measures they propose to reduce vital human activities that release CO2 to the atmosphere.  Such policies will only curtail the continued development of global prosperity, reducing our ability to ultimately eradicate these debilitating scourges from the face of the earth.

Dr. Craig D. Idso
Dr. Keith E. Idso
Vice President

Dye, C. and Reiter, P.  2000.  Temperatures without fevers?  Science 289: 1697-1698.

Rogers, D.J. and Randolph, S.E.  2000.  The global spread of malaria in a future, warmer world.  Science 289: 1763-1766.