Anthropologists estimate that humans began cooking with fire almost 2 million years ago. For some 2.7 billion people – almost one-third of the global population – little has changed about basic fuels and methods.

The vast majority of households still using open fires are concentrated in the Global South. Across Africa, Asia and Latin America, many countries report 90% of homes relying on wood, dung, crop waste and charcoal. While data are lacking on the volume of biomass that goes up in smoke each year, estimates suggest it accounts for 60% of total energy demand in Sub-Saharan Africa.

Technically, developing cleaner cooking devices and fuels is easy. But decades of failed attempts to get people to use them indicate poor understanding of personal choices, which often reflect social norms or economic constraints. Hence, the need to investigate both sides of the challenge. Click through to the topic that grabs your attention.