A new study in the American Journal of Tropical Medicine and Hygiene debunks the claim that global warming (via rising sea surface temperatures) will increase cholera outbreaks.
The notion that global warming would increase cholera outbreaks is based on the hypothesis that rising sea surface temperatures increase phytoplankton levels which, in turn, increase the population of phytoplankton-eating crustaceans to which cholera-causing bacteria attach. Then, more bacteria-bearing crustaceans increase the risk of contaminated drinking water which increases the frequency of cholera outbreaks.
As the EPA states on its web site,
Climate change may increase the risk of some infectious diseases… algal blooms could occur more frequently as temperatures warm — particularly in areas with polluted waters — in which case diseases (such as cholera) that tend to accompany algal blooms could become more frequent.
But using cholorphyll as a surrogate measure of phytoplankton over a large area, the study authors conclude,
Our results suggest that the observed positive correlation between [sea surface temperature] and chlorophyll in the Bay of Bengal is in fact not causal, and should not form the basis to infer or construct prediction models for cholera outbreaks.
Another one bites the dust. Enjoy.