It sounds too good to be true: If we could just swap out dirty indoor cooking stoves in the developing world with cleaner versions, we could cut pollution, save lives, and slow climate change. Promising, yes? But, like most things that sound too good to be true, it’s not that easy.

Too good to be true? (PR Newswire)

So, plenty of aid groups, along with Secretary of State Hillary Clinton, have endorsed the Global Alliance for Clean Cookstoves, a push to get 100 million homes around the world to adopt cleaner stoves and fuels by 2020. The technology exists. It’s cheap. It’s simple. What could go wrong?

One problem is that having a cheap, clean technology is no guarantee that it will be properly adopted. In a new NBER paper, economists Rema Hanna, Esther Duflo and Michael Greenstone note that there’s been very little evidence on whether these stoves work in the real world. They looked at a randomized control trial that handed out cleaner stoves to 15,000 people in Orissa, one of India’s poorest rural areas, and tracked the results over five years. The stoves were a bargain, costing about $12.50 a pop, and they used a chimney to keep smoke away from the users.

What Hanna and her colleagues found is that in the first year of using the stoves, households saw a serious drop in smoke inhalation. The cleaner cookstoves were working exactly as they did in the laboratory. But in the years after that, the stoves stopped working effectively. “We find no evidence of improvements in lung functioning or health and there is no change in fuel consumption (and presumably greenhouse gas emissions),” the authors write.

So what went wrong? Basically, none of the earlier evaluations of the clean cookstoves had taken into account how households in places like India would actually use the things. In early tests, there were trained technicians on hand at all times to inspect and repair the stoves. Not surprisingly, households used the stoves frequently. But when the technicians departed and the owners had to clean the chimneys themselves, they lost interest over time. People were spending too many hours conducting repairs and eventually just preferred to switch back to indoor cooking fires.

What’s more, laboratory tests had found that the more modern stoves could boil water more quickly using less fuel. This led to the idea that they could help households burn less coal and biomass overall — and so cut greenhouse-gas emissions. But Hanna and her colleagues found that the cleaner stoves did not appear to affect how long the households in Orissa actually spent cooking. “[T]here is no evidence,” they write, “of a reduction in greenhouse gas emissions.”

It’s a dismal finding. But it suggests that for aid projects — as well as for any effort to reduce greenhouse-gas emissions and tackle climate change — having the right technology won’t always be enough. “As engineers and scientists, it is easy to fixate on the technology,” concludes S.C. over at the Economist’s Free Exchange blog. “It is a lot harder, however, to predict human behaviour and how that interacts with technology.”