Almost half the world's population uses fire to cook indoors. But there's a growing realization of the negative impact many age-old cooking methods have on people's health, the environment and women's livelihoods.
On a hotel terrace on a summer's evening in Germany, conference delegates are sampling grilled vegetable kebabs that sizzle over a charcoal stove.
It's a long way from the smoke-filled kitchens of Africa, Asia and Latin America, where almost three billion people still depend on the same cooking methods as in the Stone Age - over open fires fuelled by charcoal, wood or dung - with devastating impacts on their health and the environment.
But that's exactly who those attending the Bonn International Cooking Energy Forum, held in late June, are trying to reach.
"We need to get them to understand the gravity of using three-stone fire [an open fire]," forum participant Anna Ingwe told DW. "The moment they understand, it gives them decision-making power to invest their money in the right thing."
The barbeque in Bonn demonstrated cleaner cook stove technologies and fuels to the 120 forum delegates - stove manufacturers, fuel suppliers, development organizations and field workers.
They were discussing how to reach the goal set by the Global Alliance for Clean Cookstoves: for 100 million households to adopt such technology by 2020.
The Alliance says that would improve people's health, protect the environment and empower women, who are traditionally responsible for collecting fuel and cooking.
It's estimated polluting, inefficient stoves contribute to about four million deaths each year.
When traditional open fires are used inside without adequate ventilation, toxic smoke and particles quickly fill homes. Continued exposure to the pollution can cause a long list of health issues like pneumonia, lung diseases, cancers, pregnancy complications, strokes, cardiovascular diseases and cataracts.
"Safe energy and the right to have clean air to breathe every day is a major determinant of our health, and therefore we need to fight for it," Dr. Maria Neira, director of public health and environment at the World Health Organization, told DW.
Strain on time, budget, environment
Nawa Raj Dhakal has seen the health effects first-hand, watching his mother and grandmother cook during his childhood in rural Nepal.
"They used to go far away to collect firewood and when they burnt it," said the assistant director of Nepal's Alternative Energy Promotion Center. "It used to be very smoky inside the house, so they used to suffer from a lot of smoke-related diseases or illnesses like eye irritations, coughing and respiratory problems," he said.
Reliance on wood or charcoal forces women and children to spend up to 12 hours collecting fuel and cooking each day.
If there is not much fuel available to gather, families must buy it, which strains their budgets and means less money can be spent on the food itself, affecting the health of the whole household.
Because traditional stoves are so inefficient, large amounts of fuel must be collected, which puts pressure on forests. More than three million tons of firewood is burnt under pots and pans each day, resulting in large emissions of carbon dioxide, a contributor to climate change.
Changing a mindset
However, it's not easy to get people to adopt new cooking methods when their communities have been doing the same thing for thousands of years.
Anna Ingwe, who grew up in rural Tanzania and now works in Kenya for the GIZ, Germany's Society for International Cooperation, recalls spending hours collecting firewood as a child. Despite having worked for the past decade to promote clean cook stoves, she struggles to convince her own mother to use one.
For women to embrace cleaner cooking, they needed to truly understand the link between the smoke and their own ill health, Ingwe said.
"To buy or not to buy a stove is not a matter of affordability. There is more to it than that," said Ingwe. "There is the issue of priority. When a mother gets her money, she may have a sick child, a kid who is going without shoes to school. It really depends on what's at hand at that moment."
Alliance for change
To tackle the problems, the Global Alliance for Clean Cookstoves was formed in 2010, led by the United Nations Foundation. It brings together 700 scientists, non-government organizations, national agencies and stove makers.
Efficient charcoal stoves like this one, demonstrated in Bonn, are part of the solution to indoor air pollution
While the Alliance is still working to confirm standards for what counts as clean and efficient, the options include charcoal or wood stoves with better burning technology and cookers powered by LPG, biogas, alcohol and solar, said its executive director, Radha Muthiah.
The Alliance aims to create a thriving global market so businesses can develop stoves that work for their own communities, environmental conditions and local cuisine.
Today, about three million cleaner stoves are being used that qualify toward its 100 million goal.
"We've seen that once people understand the benefits - however they realize those benefits, whether it's health or economic or time - they're much more willing to buy the right product for themselves and continue using that product as well," Muthiah said.