A British-funded research team has found that global warming has caused a seven-fold increase in cases of malaria on the slopes of Mount Kenya.
According to a report in The Times, a 2 degree Celsius increase in average temperatures around the mountain in the past 20 years has allowed the disease to creep into higher altitude areas, where the local population of four million has little or no immunity.
The researchers, funded by the Department for International Development (DfID), found that the average temperature in the Kenyan Central Highlands had risen from 17C in 1989 to 19C today.
Before the 1990s, malaria was absent from the region because the parasite that causes it can mature only above 18 degree C.
However, malaria epidemics began among the population as average temperatures went over the 18C tipping point.
The number of people contracting malaria during these epidemics has increased seven-fold in the past decade.
In 2005, malaria-carrying anopheles mosquitoes were discovered in Naru Moro, more than 6,175ft (1,900m) above sea level.
The team, from the Kenyan Medical Research Institute, said that while similar outbreaks elsewhere had been attributed to multiple factors, including drug resistance and changes in land use, the only change here had been the rise in temperature.
A DfID spokesman said the research had also concluded that emissions from human activity, rather than natural climate variability, were responsible for the change in temperature.
"The seven-fold increase is directly attributable to man-made climate change. One of the problems in making the link between climate change and malaria is that natural factors usually have a part to play," he said.
"For instance, some claim that the recent outbreak of malaria around Nairobi has been caused by climate change when in fact this probably has more to do with changes in drainage systems and population expansion. But in the Central Highlands the researchers have been able to rule these out and directly attribute the change to a 2C increase in the average temperature," he added.
According to Douglas Alexander, the International Development Secretary, "The spread of malaria in the Mount Kenya region is a worrying sign of things to come."