Indeed, the cost of health impacts (e.g. diarrheal disease and cancer) is expected to be around 1.9% of rural GDP (World Bank, 2007b). Improving wood fuel efficiency or finding alternative sustainable fuels could reduce indoor smoke pollution and consequently mitigate health risks, reduce deforestation, and have positive spillovers on soil conservation, watershed management, irrigation agriculture and biodiversity conservation (World Bank, 2009b). Also, problems of droughts and desertification pose great environmental challenges in Tanzania, particularly the agricultural sector and rural communities. In general, Tanzania has experienced decreasing rainfall and increasing temperature.