The health impacts of climate change: a study of cholera in Tanzania

Abstract

Increased temperatures and changes in patterns of rainfall as a result of climate change are widely recognized to entail serious consequences for human health, including the risk of diarrheal diseases. Indeed, there is strong evidence that temperature and rainfall patterns affect the disease pattern. This paper presents the first study that links the incidence of cholera to environmental and socioeconomic factors and uses that relationship to predict how climate change will affect the incidence of cholera. Specifically, the paper integrates historical data on temperature and rainfall with the burden of disease from cholera in Tanzania, and uses socioeconomic data to control for impacts of general development on the risk of cholera. Based on these results we estimate the number and costs of additional cholera cases and deaths that can be attributed to climate change by year 2030 in Tanzania. The analyses are based on primary data collected from the Ministry of Health, Tanzania, and the Tanzania Meteorological Agency. The result shows a significant relationship between cholera cases and temperature and predicts an increase in the initial risk ratio for cholera in Tanzania in the range of 23 to 51 percent for a 1 degree Celsius increase in annual mean temperature. The cost of reactive adaptation to cholera attributed to climate change impacts by year 2030 in Tanzania is projected to be in the range of 0.02 to 0.09 percent of GDP for the lower and upper bounds respectively. Total costs, including loss of lives are estimated in the range of 1.4 to 7.8 percent of GDP by year 2030. Lastly, costs of additional cholera cases and deaths attributed to climate change impacts in Tanzania by the year 2030 largely exceed the costs of preventive measures such as household chlorination.