Int. J. Environ. Res. Public Health 2011, 8 8. Effects of Climate to Date and Projections The calculated elasticity is used to estimate both 924  the consequences of recent climate change on the observed malaria cases to date and  the effects of projected climate change in 2080 to 2099 to cases that would be observed under those conditions. Between 1961 and 1990, the IPCC indicates average global temperatures have been increasing at the rate of 0.2 degree Celsius per decade [21] but precipitation has decreased by about 5–10 percent across the African continent [44]. We evaluated the effects of this on the estimated malaria cases using the elasticities estimated above. In particular we calculated for each country the change in temperature in degree Celsius and the percentage change in precipitation levels between the 1980–1989 decade and the 1990–2000 decade and used these values to estimate the effect of climate on malaria prevalence for these 20 years. The results are compiled in Table 3. These results show that excepting Benin, Burkina, Chad, Ethiopia, Ghana, Guinea, Sudan and Togo that all of the study region countries had an increase in the number of malaria cases due to climate change. The effect on the disease was particularly large in Algeria, Central African Republic, Djibouti, Egypt, Malawi and Morocco where we compute that recent climate change has contributed more than 21% increase in the number malaria of cases per 1,000 people. The effects of future climate change on potential malaria cases was also estimated using projected temperature and precipitation alterations for 2100 drawn from 21 global climate models for the A1B emission scenario [21]. Temperature and precipitation projection values for Africa are not available at country level but rather for five larger regions (West, East, South, North and Mediterranean). The countries were assigned the projection for the region in which they fell. The potential changes in the number of malaria cases were computed at the minimum, median and maximum projected temperature/precipitation values corresponding respectively to scenario 1, scenario 2 and scenario 3 malaria cases projection in the Table 4. We found both positive and negative responses in the number of malaria cases depending on country and climate change scenarios. All but three countries showed a projected increase in the total number of cases across climate change scenarios. In the endemic zone around the equator the only countries to show a reduction across scenarios are Central African Republic, Ethiopia and Guinea. The general observation is that climate change is likely to enhance the number of cases in countries with high levels of currently infected people excepting a few countries. In particular, all other things held constant countries such as Algeria, Benin, Burkina, Burundi, Cote D’Ivoire, Djibouti, Egypt, Ghana, Malawi, Mauritania, Niger, Rwanda, Sudan, and Togo would see their malaria prevalence rate per 1,000 people increase more than 25% across climate change scenarios.