Cookstove experts are calling out recent research on ‘Cookstoves Offset Methodologies’ as misguided and threatening to critical funding for clean alternatives to solid fuel stoves – affecting the health and lives of 2.3 billion people.
The undersigned researchers and experts on energy poverty and improved cooking in low-income countries are writing to 1) express methodological concerns about a recent publicly posted document entitled “Cooking the Books: Pervasive Overcrediting from Cookstoves Offset Methodologies” by Annelise Gill-Wiehl, Daniel Kammen, and Barbara Haya of University of California, Berkeley (hereafter referred to as Gill-Wiehl et al., 2023) and 2) call for the funding of primary and unbiased research on the climate and social impacts of the growing field of climate financed improved cookstove projects. Our collective expertise from designing, implementing, monitoring, and researching cookstove projects across Africa, Latin America, and Asia informs these comments.
Kindly note that the technical substantiation for the following concerns can be found below the signatories of this letter.
- Unsubstantiated Assumption: The authors rely on the unsubstantiated assumption that the design, target population, and performance of cookstove projects in the academic literature selected by the authors are representative of the design, target populations, and performance of cookstove projects financed by carbon offset credits. This assumption is incorrect.
- Incomplete and Selective Review of the Academic Literature: The minimum and maximum values input into the Monte Carlo Analysis (a mathematical technique that predicts possible outcomes of an uncertain event) determine the findings of the analysis. A cursory review found relevant findings of highly regarded research1 outside the figures considered in the Monte Carlo Analysis, the entire range of which is typically included in this Analysis. These omissions suggest a fundamental problem with the paper inputs and the limitations of a Monte Carlo Analysis in this context.
- Unrepresentative Sampling of Carbon Cookstove Projects: The sample of cookstove carbon projects was first constructed by selecting the largest projects by quantity of credits produced in certain countries – an attribute which is correlated with higher per-stove crediting. Accordingly, this method of sample selection introduces a selection bias into an analysis that claims to arrive at findings representative of the entire carbon cookstove market. A second version of the paper obscured the selection methodology as “purposive.” Because carbon financed cookstove projects are not adequately similar to the cookstove projects in the academic literature selected by the authors, even a comparison to 100% of cookstove carbon projects wouldn’t allow meaningful inference. The opaque sampling methods, applied by researchers who understand sampling bias, raise concerns about the integrity of the analysis.
- Conflict of Interest and Possible Bias: We also note that financing for the analysis was provided by The Better Cooking Company, a venture-backed company seeking to create carbon credits on a type of stove project2 which the authors favor and call on to be “prioritized.” Carbon Direct, a New York-based company, is also listed as a funder of Dr. Haya. Carbon Direct’s business focuses on selling carbon removal credits that compete with carbon reduction credits, such as those from cookstove projects. The authors disclose The Better Cooking Company was offered an opportunity to review the document prior to its publication.
In striving for the advancement of knowledge and the betterment of the world’s marginalized cooks, the cookstove community places immense value on accurate and well-founded research. The methodologies employed by climate-financed projects in the cookstove domain have been rigorously scrutinized and enriched through extensive peer reviews and the contributions of scientific experts across numerous years and continue to improve. In fact, significant progress has been made by the Clean Cooking and Climate Consortium (4C)—a group of partners convened by the Clean Cooking Alliance—to use modern science to build upon past methodologies for clean cookstove project.3
The paper in question coherently summarizes many of the issues of ongoing discussion within the cookstove community, particularly concerning the improvement of fuel carbon intensity and the use of United Nations approved fNRB (fraction of non-renewable biomasses) assessment methods and charcoal-to-wood ratios, both of which are presently undergoing comprehensive evaluations at various levels. These discussions underscore the need for more profound analyses and untainted primary research, which can subsequently refine and enhance the methodologies employed.
It is important to reiterate for the carbon offset community that the development of improved methodologies and deployment strategies is rooted in the desire for good public health and environmental science and, ultimately, to empower disadvantaged individuals with efficient and smoke-free cooking solutions that also have a climate impact. In light of this, the significance of meticulous research cannot be overstated.
However, concern arises when evaluating the conclusions drawn by Gill-Wiehl et al., 2023. These conclusions rest upon an examination of academic literature that has omitted the examination of substantial subsets of carbon cookstove projects. The potential bias in the selection of the sample, the reference studies, and Monte Carlo inputs, and the clear absence of a well-rounded review and consideration of existing literature further undermine the integrity of the study’s findings. Moreover, the study has received funding from parties with vested interests in the results of the author’s findings and clear conflicts of interest, raising concerns about the intentions of the study. Such an approach not only veers away from objective truth but diminishes the credibility of the study itself. As a community committed to meaningful progress, it’s crucial that we uphold rigorous research standards and embrace a spirit of transparency and inclusiveness.
1 Ruiz-Mercado et al. 2013. “Quantitative Metrics of Stove Adoption Using Stove Use Monitors (SUMs)”. Biomass and Bioenergy 57: 136-148.