Figure 3 Potential risk areas for contracting malaria (P. falciparum) expressed in units of average annual "epidemic potential": (a) for climate conditions typical of the period 1931- 1980; (b) the same, as computed for an increase in global mean surface temperature of 1.2°C (about 2.4°F, and the IPCC "best estimate" for the year 2050), based on climate patterns generated by a General Circulation Model of the Max Planck Institute in Germany. The third map (c) shows projected changes relative to the base-line period. The epidemic potential expresses the likelihood that conditions conducive to malaria will prevail in a given area. The epidemiological models that are employed include the effects of seasonal temperature and precipitation on the survival, development, and number of mosquitoes, the biting rate, parasite incubation rates, and the susceptibility of humans and mosquitoes to P. falciparum. Based on W. J. M Martens et al., Climatic Change, vol 35, pp 145-156, 1997.