Traditional use of biomass in form of firewood, charcoal, manure and crop residues continues to play a major role in many developing countries. It represents the largest contribution to the energy supply to many dispersed and poor rural populations where it is used inefficiently in open hearths or simple stoves in poorly ventilated spaces to cook food.
Apart from being energetically inefficient and time consuming, the use of traditional bioenergy is connected to several severe health and environmental problems:
Studies have shown that the inefficient use of bioenergy results in significant exposure to indoor air pollution. Women, children and the elderly face higher risks due to long hours spent around solid fuel based fires. According to the World Health Organization, indoor air pollution is at present responsible for 2.7% of the total burden of disease.
Traditional use of biomass, especially charcoal, is often linked to degradation of forests and woodland resources as well as soil erosion.
Cooking using traditional fuels leads to emissions of greenhouse gases and soot (black carbon) due to poor combustion (the latter contributes to global warming through absorption of incoming radiation. These emissions are believed to represent on the order of 5% of total global warming derived from human activities.
The problems associated with traditional use of biomass are complex, as they are highly correlated with people's income levels, living habits, village structures and gender roles. Projects that support setting up businesses that offer alternatives such as more efficient stoves and switching to cleaner fuels have helped to improve the situation, but the problem persists.