Kyle W. Knight and Eugene A. Rosa, “Household Dynamics and Fuelwood Consumption in Developing Countries: A Cross-national Analysis,” Population and Environment, vol. 33, no. 4 (June 2012), pp. 365–78, https://doi.org/10.1007/s11111-011-0151-3. This paper was collaboratively assessed.
A study of fuelwood consumption, household size and numbers, and population in 87 developing countries found that decreasing household size tends to boost the amount of fuel that each person in a population consumes. This leads to the paradoxical conclusion that reduced fertility—which slows population growth but also contributes to smaller household size—makes an independent contribution to greater fuelwood consumption.
Growth in population is likely a larger net driver than increased per capita consumption caused by smaller households to a country’s total increase in fuelwood use.
Yet the authors also found that growth in population is likely a larger net driver than increased per capita consumption caused by smaller households to a country’s total increase in fuelwood use. When the greater population is multiplied by the higher per capita fuelwood consumption, it is the former multiplier that exerts more influence on the equation’s sum. Some 3 billion people, overwhelmingly in developing countries, rely on fuelwood for cooking and heat, which the authors assert contributes at least marginally to deforestation and perhaps more significantly to the deterioration of forest habitat and the degradation of biodiversity.
Some 3 billion people, overwhelmingly in developing countries, rely on fuelwood for cooking and heat.
The authors applied a model based in the STIRPAT equation to tease out the various influences on change in fuelwood consumption in each country. (STIRPAT builds on the classic population-environment equation IPAT, which stands for “environmental impact equals population times affluence times technology.” STIRPAT adds the words “stochastic impacts by regression” to the acronym, and includes analysis of how human and environmental forces interact over time.) The authors cite earlier literature also finding that lower fertility can contribute to smaller households and, through this, higher per capita consumption. (They note that other forces also can lead to smaller households, such as increases in divorce and cultural shifts away from living in extended families.) They suggest that this complex relationship between lower fertility, population growth, and per capita and total consumption may affect biodiversity and natural resources other than fuelwood in developed as well as developing countries.
“Population size is a major driving force of resource consumption and environmental degradation.”
Key quotes: “Consistent with previous research, total population has a significant, positive effect on total fuelwood consumption [in the study’s primary model]. This supports the widely verified finding that population size is a major driving force of resource consumption and environmental degradation. . . . [W]hile family planning and associated policies and programs are the typical response to population growth, our results indicate that these responses may have unintended consequences that diminish their environmental benefits. In particular, reducing fertility rates decreases population growth, but at the same time may contribute to decreasing household sizes and growth in the number of households.”
FPESA network assessments (seven total) were mostly favorable, with one assessor suggesting that the consumption-increasing impacts of lower fertility found in this study should be made more clear in the FPESA conceptual framework. The paper was seen as clear and understandable and the study as reproducible, ideally with data for more countries if they could be found. Two assessors criticized methodological aspects of the authors’ model. One of these also wished for more ideas in the paper on how to address the greater consumption of smaller households. A third assessor felt that the study failed to examine what it is about the fertility-household size connection that increases per capita consumption—possibly a connection to increasing affluence (not explored in the study) as much or more than economies of household scale (which was explored). A few assessors missed a deeper exploration on whether, how, and to what extent family planning and lower fertility themselves directly or indirectly affect per capita consumption, ideally compared to other factors, and suggested that this key question for the FPESA hypothesis remains unanswered.
Overall assessment: This study is the clearest that we evaluated that explores an important feature in our conceptual framework: the dashed arrow and box leading from lower fertility to higher per capita consumption as a possible confounding effect in the family planning-environmental sustainability linkage. Using a statistical model in what appears to be a sensible way and focusing on consumption of a key resource in developing countries, the authors make an important finding. Reducing the size of households (a likely outcome of the use of family planning, although this link is not closely examined) tends to increase the per capita consumption of fuelwood in a country. This undermines what the authors contend is the overall environmental benefit of slowing population growth, although they find that the effect does not overwhelm that benefit altogether. As several assessors noted, the study is well crafted and communicated and offers an important finding. Yet it is hardly definitive, and the questions of whether the use of family planning increases per capita consumption and how this might affect a population’s total consumption over time remain to be more fully explored.
As an added bonus, the authors include in a footnote a helpful discussion of the terms “driving forces” and “drivers,” which have been seen as controversial and sensitive in the context of discussing how population growth affects the environment: “The term ‘driving forces’ or ‘drivers,’ familiar to several areas of research in the physical sciences such as plate tectonics and statistical thermodynamics, is new to the social sciences. More importantly, it has been universally adopted by natural scientists studying global environmental change to refer to what are presumed to be the most important factors producing environmental change. In the more generic language of science they are independent variables, particularly ones shown to have environmental effects.”
Robert Engelman is a senior fellow at Worldwatch and director of its Family Planning and Environmental Sustainability Assessment project. You can read his latest report, Assessing the Science, free online.
The following annotation and assessment is excerpted from the just-released report of the Family Planning and Environmental Sustainability Assessment (FPESA) project. The report contains selected annotations from 939 peer-reviewed articles reviewed for potential relevance to the hypothesis that family planning supports environmental sustainability. The annotations are written by project director Robert Engelman with input from members of the project team and, where indicated, members of the project’s international network of research assessors.