Clean Cookstoves
2.1 billion people cook on open fires. The smoke kills around three million a year, mostly women and children. This is the deadliest environmental problem on Earth and the least funded.
The effect is immediate. This stops an emission that is happening right now.
Origins
The open fire is the oldest human technology and it is still the primary cooking method for a quarter of the planet.
It is also, in an enclosed room, a slow poison. A woman cooking over a wood or dung fire inhales, over the course of a day, a quantity of fine particulate matter comparable to smoking a substantial number of cigarettes. She does it while pregnant. She does it with an infant tied to her back, at exactly the height of the smoke. And she does it because there is no alternative, and because collecting the fuel already takes hours of her day.
The scale of the harm was invisible for most of the twentieth century because it happened indoors, to poor women, in villages, and nobody was counting. When the Global Burden of Disease studies finally counted, household air pollution turned out to be one of the largest single environmental killers on the planet.
The response, from the 1980s onward, was the improved cookstove: a better-designed biomass stove that burned wood more efficiently and vented some of the smoke. Hundreds of millions of dollars went into distributing them, and enormous numbers were deployed.
And here we have to be honest, because the sector has not always been: they largely did not work. Not well enough. The Cooking and Pneumonia Study in Malawi — the largest randomised trial ever conducted on biomass cookstoves — found that cleaner-burning biomass stoves did not significantly reduce pneumonia in young children. The improvement was real and it was insufficient. The exposure stayed above the level at which health improves.
That result reorganised the field, and it is the most important thing on this page.
What it actually is
The lesson of thirty years of cookstove programmes is uncomfortable and clear: improving the stove is not enough. You have to change the fuel.
Burning solid fuel — wood, dung, crop residue, charcoal, coal — in any device produces fine particulate matter and carbon monoxide, and even a good stove leaves exposure well above WHO guideline levels. The dose-response curve for these pollutants is brutally non-linear: you have to cut exposure a very long way before health outcomes move at all. A stove that halves the smoke may deliver almost no measurable health benefit, which is exactly what the trials found.
What does work is moving up what practitioners call the energy ladder, to fuels that do not produce that smoke: LPG, electricity, biogas, ethanol. LPG is a fossil fuel, and that is an awkward thing for a climate page to advocate, and we are going to say it anyway: for a woman cooking over dung in a closed kitchen, LPG is a very large improvement in her life expectancy and her children’s, and its climate impact is modest compared with the black carbon and deforestation it displaces. Electric cooking, powered by an increasingly clean grid or by solar, is the destination.
The climate case is real but it is the secondary one. Residential cooking emits roughly a gigaton of CO₂-equivalent a year, around 3% of the global total, plus black carbon — a short-lived but intensely warming pollutant — and it drives deforestation for fuelwood and charcoal across much of Africa and South Asia.
But the reason to do this is that the smoke is killing three million people a year.
The numbers
The people. Around 2.1 billion people — roughly a quarter of humanity — still cook using open fires or inefficient stoves burning biomass, coal or kerosene (WHO).
The deaths. Household air pollution was responsible for an estimated 3.2 million deaths in 2020, and around 2.9 million in 2021, including over 300,000 children under five. Combined with outdoor air pollution, some 6.7 million premature deaths a year.
Who dies. In Africa, women and children account for roughly 60% of early deaths from household smoke (IEA). This is not a coincidence of exposure. It is who stands at the fire.
The climate. Residential cooking emits roughly 1 gigaton of CO₂-eq annually, about 3% of the global total, plus black carbon, which warms intensely and is short-lived — meaning reducing it acts fast.
The progress, which is real. The share of the world relying mainly on polluting cooking fuels fell from over half in 1990 to 29% by 2021, producing a 36% reduction in deaths from household air pollution since 2000. This is one of the great unremarked public health achievements of our era.
The money. The IEA estimates that US$10 billion a year would achieve universal clean cooking access by 2030. Current investment is a small fraction of that. It is, by a wide margin, the most underfunded major environmental health problem in the world.
The finding that should change your mind. The largest randomised trial of cleaner-burning biomass cookstoves — the Cooking and Pneumonia Study in Malawi — found no significant reduction in childhood pneumonia. Improving the stove is not enough. The fuel has to change.
Why it matters
Three million people a year die from the smoke of their own kitchens, and almost nobody in a wealthy country has ever heard of this.
It does not have a march. It does not have a documentary. It is not on anybody’s placard. It kills more people annually than malaria, and it has done so, quietly, in kitchens, for the entire history of our species, and the reason nobody talks about it is that it happens to poor women indoors and it has never happened to us.
Every one of our grandmothers cooked over a fire, somewhere back along the line. In most of the world that line has not yet been crossed. The woman in a village in Malawi or Bihar, cooking over dung with a baby on her back, is not living in a different moral universe from your great-grandmother. She is living in a different decade, and the only thing standing between her and clean air is about ten billion dollars a year — roughly what the world spends on chewing gum.
We include this page not because of the gigaton, though the gigaton is real. We include it because a climate movement that cannot see the woman at the fire is not seeing the world.
She is not a beneficiary. She is spending four hours a day gathering fuel that is poisoning her children, on land that is being deforested to supply it, and she knows all of this perfectly well. She does not need to be persuaded. She needs a different stove and a different fuel, and she needs someone to notice.
What it actually takes
Accepting that the improved biomass stove was mostly a failure. This is hard for a sector that spent thirty years and enormous sums on it, and it is necessary. The trials are clear. Incremental improvement to solid-fuel burning does not move health outcomes, because the dose-response curve does not work that way.
Fuel switching, which means confronting LPG honestly. LPG is a fossil fuel and it is also, for hundreds of millions of people, the fastest available route out of a kitchen that is killing them. A climate movement that opposes it on principle is asking the poorest women on Earth to wait for a clean grid that may be twenty years away. We think that is indefensible, and we think saying so plainly is more useful than pretending the tension does not exist.
Electric cooking is the destination. As grids clean up and off-grid solar becomes cheaper, electric cooking becomes both the healthiest and the cleanest option. This is where the money should be going.
Affordability and supply, not just distribution. The graveyard of cookstove programmes is full of stoves that were given away and then not used, because the fuel was too expensive, or the supply was unreliable, or it did not cook the food people actually eat. A stove that cannot make injera or chapati properly will be abandoned no matter how clean it is.
Asking the women. An extraordinary number of these programmes were designed by engineers who had never cooked the food in question.
Where it matters most
Sub-Saharan Africa is where the problem is deepest and getting worse in absolute terms, because population growth is outpacing access. The East African Rift, the Guinean forests and the southern African savanna are all being deforested substantially for cooking fuel and charcoal.
The Indian subcontinent is where the largest single population still cooks with solid fuel, and where India’s LPG expansion programme has been one of the largest and fastest public health interventions of the century — imperfect, criticised, and unquestionably life-saving.
The Sahel is where fuelwood collection intersects with desertification and with the safety of women, who walk further each year for wood and are attacked doing it.
The Himalayan valleys and Tibetan Plateau are where black carbon from cooking fires settles on snow and ice, darkening it, accelerating melt, and threatening the water supply of a very large part of Asia.
How to tell it’s being done well
Is the fuel changing, or just the stove? This is the question. Thirty years of evidence says that improving biomass combustion does not move health outcomes far enough. If a programme is distributing better wood stoves, ask what exposure reduction they have actually measured.
Are they measuring exposure, or distribution? Stoves distributed is the metric of a failed sector. Personal exposure to PM2.5, measured on the woman doing the cooking, is the metric that matters.
Are the stoves still being used in year three? Abandonment rates in cookstove programmes have been notoriously high and notoriously under-reported.
Can it cook the actual food? A stove that cannot make the staple bread of the region is a stove that will end up in a shed.
Is the fuel supply reliable and affordable? A clean stove with no fuel is worse than useless: it is a broken promise.
What you can do
Anyone
- Learn that this exists. Household air pollution kills around three million people a year and is almost entirely absent from environmental conversation in wealthy countries.
- Support organizations working on clean cooking. The IEA estimates 10 billion dollars a year would solve it, and current funding is a fraction of that. This is the most underfunded major environmental health problem on Earth.
Policymakers and funders
- Fund fuel transition, not stove distribution. The evidence that improved biomass stoves fail to deliver health benefits is now strong and it should reorganise where the money goes.
- Do not let climate purism block LPG for the poorest. For a woman cooking over dung, LPG is a large gain in life expectancy, and the climate cost is modest against the black carbon and deforestation it displaces.
- Electric cooking is the destination. As grids clean and off-grid solar cheapens, that is where investment should concentrate.
Practitioners
- Measure personal exposure, not stoves distributed. The sector has been reporting the wrong number for thirty years.
- Ask the women who will cook on it, before you design it. An astonishing number of these programmes were not.
- Check adoption at year three. Abandonment has been high and under-reported.
Business and investors
- Off-grid solar plus efficient electric cooking is a large, underserved market with an enormous social return.
- Fuel supply chains, not just devices. A clean stove without reliable affordable fuel is abandoned within a year.
Who is working on this
We are researching which organizations in our directory of 8,493 actively work on this solution, and we only list an organization once we have verified it. That research is ongoing. In the meantime, search the directory yourself:
Questions
How many people are affected?
Around 2.1 billion people, roughly a quarter of humanity, still cook using open fires or inefficient stoves burning biomass, coal or kerosene. Household air pollution was responsible for an estimated 3.2 million deaths in 2020, including over 300,000 children under five. In Africa, women and children account for about 60% of those deaths.
Do improved cookstoves actually work?
Largely, no, and this is the most important thing on this page. The Cooking and Pneumonia Study in Malawi, the largest randomised trial of cleaner-burning biomass cookstoves ever conducted, found no significant reduction in childhood pneumonia. The dose-response curve for these pollutants is non-linear: you have to cut exposure a very long way before health improves, and a better wood stove does not go far enough.
So what does work?
Changing the fuel, not just the stove. Moving to LPG, electricity, biogas or ethanol removes the smoke rather than reducing it. Electric cooking, powered by a cleaning grid or off-grid solar, is the destination.
Isn't LPG a fossil fuel?
Yes, and this is a genuine tension we will not pretend away. For a woman cooking over dung in a closed kitchen, LPG is a very large gain in her life expectancy and her children's, and its climate impact is modest against the black carbon and deforestation it displaces. A climate movement that opposes it on principle is asking the poorest women on Earth to wait for a clean grid that may be twenty years away.
Is this really a climate solution?
It is, though the health case is far stronger. Residential cooking emits roughly a gigaton of CO2-equivalent a year, about 3% of the global total, plus black carbon, which warms intensely and is short-lived, meaning cutting it acts fast. It also drives deforestation for fuelwood and charcoal across much of Africa and South Asia.
Is anything getting better?
Yes, substantially, and it is barely reported. The share of the world relying mainly on polluting cooking fuels fell from over half in 1990 to 29% by 2021, producing a 36% reduction in deaths from household air pollution since 2000. The IEA estimates that 10 billion dollars a year would finish the job by 2030.
Sources
- Project Drawdown - Improve Clean Cooking (Drawdown Explorer) Framework and classification. Cited, not reproduced.
- WHO - Household air pollution and health
- Mortimer et al. (2017), The Lancet - Cooking and Pneumonia Study (CAPS), Malawi
- IEA - Access to clean cooking
- Clean Cooking Alliance
The solution taxonomy follows the framework popularised by Project Drawdown. The analysis above is our own; for their carbon modeling and rankings, visit them directly.