By Paul Homewood
In 2000, four researchers led by G D Shanks carried out a detailed study into the apparent rise in malaria admissions at the hospital which Brooke Bond run at their tea estates in Kenya.
This was their Abstract:
The changing epidemiology of clinical malaria since 1965 among hospitalized patients was studied at a group of tea estates in the western highlands of Kenya. These data indicate recent dramatic increases in the numbers of malaria admissions (6·5 to 32·5% of all admissions), case fatality (1·3 to 6%) and patients originating from low-risk, highland areas (34 to 59%). Climate change, environmental management, population migration, and breakdown in health service provision seem unlikely explanations for this changing disease pattern. The coincident arrival of chloroquine resistance during the late 1980s in the sub-region suggests that drug resistance is a key factor in the current pattern and burden of malaria among this highland population.
In particular, when they looked at climate data, they found:
Climate data were available between 1965 and 1997 as mean monthly ambient temperature (°C) and monthly rainfall totals (mm) recorded at the centre of the estates by the Tea Research Foundation (Ng’etich, 1997). There has been no significant change in the mean annual monthly mean temperature (B = 0·009 (°C/year), r2 = 0·04, P = 0·14, not significant) or mean annual monthly total rainfall (B = −0·232 (mm/year), r2 = −0·03, P = 0·642, not significant) during the period 1965–97. While these analyses do not exclude complex, combined temperature and rainfall changes it seems plausible to assume that factors other than climate change would have led to the precipitous rise in malaria warranting inpatient care during the 1990s at the Kericho tea estates.
But as we know, the climate industry is not happy with results like this, so another new study was funded, and published by Alonso et al in 2010:
Climate change impacts on malaria are typically assessed with scenarios for the long-term future. Here we focus instead on the recent past (1970-2003) to address whether warmer temperatures have already increased the incidence of malaria in a highland region of East Africa. Our analyses rely on a new coupled mosquito-human model of malaria, which we use to compare projected disease levels with and without the observed temperature trend. Predicted malaria cases exhibit a highly nonlinear response to warming, with a significant increase from the 1970s to the 1990s, although typical epidemic sizes are below those observed. These findings suggest that climate change has already played an important role in the exacerbation of malaria in this region. As the observed changes in malaria are even larger than those predicted by our model, other factors previously suggested to explain all of the increase in malaria may be enhancing the impact of climate change.
The difference between the two papers is stark. The Shanks study starts with an open mind and considers the data objectively.
The Alonso one starts with the objective of proving that climate change is to blame, and then uses computer models to confirm their bias.