Finance the replacement of a traditional cooking stove with a system that emits less toxic smoke and CO2 in developing countries can make it possible to obtain carbon credits, but the environmental benefits claimed by these projects are largely overestimated, a new study reveals.
After accusing carbon credits linked to projects aimed at preventing deforestation last summer of exaggerating their CO emissions reductions2a team from the University of Berkeley in California published on Tuesday a study feared by the voluntary carbon market, whose credibility has collapsed over the last two years.
“Approximately 2.4 billion people cook using solid fuels that emit smoke or oil, leading to the premature deaths of 2 to 3 million people per year and around 2% of gas emissions greenhouse effect in the world”, explain Barbara Haya, Annelise Gill-Wiehl and Daniel M. Kammen in the introduction to their article published by the journal Nature Sustainability.
Replacing traditional systems — often three stones around a pile of charcoal — is beneficial for reducing CO emissions2mainly responsible for global warming, but also for health by improving indoor air quality and reducing gender inequalities, poverty and deforestation.
Carbon credits “have the potential to provide considerable financing” for these projects, which represent less than 10% of the voluntary carbon market, the researchers recognize.
One carbon credit is equivalent to one ton of CO2 stored or prevented from entering the atmosphere thanks to a project. These credits can be purchased by companies, states or individuals to offset their own greenhouse gas emissions and call themselves “carbon neutral”.
Biased responses
The problem lies, according to the study’s conclusions, in the methodologies which make it possible to determine the number of credits issued and overestimate CO emissions by up to ten times.2 avoided.
The cause is a “lack of rigor” and too much “flexibility” of the criteria established by the five most used methods.
For example, in one of them, if a household claims to have used the new cooking system at least once during the past week or month, credits are generated for the two years over which the cooking system extends. project, with a penalty only if the household indicates having used its old system at least once over the same period.
It also happens that participants answer “what they think the people conducting the questionnaire (hired by the project developers) expect of them”, by inflating the figures.
Bias also occurs in the measurement of household fuel consumption or in the estimates of deforestation avoided thanks to the reduced use of wood for cooking.
By applying their own methodology to 51 projects in 25 countries (Uganda, Sudan, Haiti, Mexico, Ghana, Bangladesh, India…) which represent 40% of carbon credits linked to cooking stoves in the world, the sentence is final : 26.7 million carbon credits were thus generated… while only 2.9 million tonnes of CO2 were avoided, almost ten times less than the project developers claim.
To avoid overestimations, the researchers decided to use the most “conservative” assumptions. Barbara Haya extends this recommendation to all carbon credits, accused of greatly overestimating their social and environmental benefits after the publication of several surveys and academic studies.
While a version of the study not yet peer-reviewed was circulating, players in the voluntary carbon market, brought together by S&P Global in Paris in November, were concerned about the repercussions of this publication, with some calling on the media and researchers not to “exaggerate exaggerations”.
“A carbon credit market based on exaggeration is doomed to failure,” replies Barbara Haya to AFP, claiming to have limited the margins of error as much as possible.
But “if our recommendations are adopted, this type of project could be one of the few to be credible for buyers of carbon credits”.