Contrary to conventional wisdom, the use of fossil fuels for household cooking and heating may make more environmental sense for the estimated 2 billion rural poor in the world, according to a researcher from the University of California, Berkeley. Because they contribute to greenhouse gas emissions, fossil fuels have been largely dismissed as a viable alternative for the one-third of the world’s population who now use coal and local biomass – including wood, crop residues and dung – for cooking and heating, said Kirk R. Smith, professor and chair of environmental health sciences at UC Berkeley’s School of Public Health. Efforts have been focused on equipping the rural poor with renewable energy sources, such as solar and wind power.