Published on Let's Talk Development

Exploring the link between polygyny and farm households’ resilience to climate shocks

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People searching for water in Tanzania. People searching for water in Tanzania.

Droughts have long been constant threats to livelihoods in the developing world, increasing both short-term and long-term risks especially in smallholder farmers’ communities. The literature finds that community-based risk-sharing mechanisms break down in the presence of spatially covariant risks such as droughts (Kazianga and Udry, 2006; Fafchamps and Gubert, 2007), and household resilience strategies to such shocks become positively correlated with household size (Toulmin and Gueye, 2003; Banda et al., 2016). This finding suggests that fertility may have overarching importance in drought-prone village economies. Evidence points that polygyny—increases fertility (Tertilt, 2005; Rossi, 2019), and is highly prevalent in drought-prone rural communities in Sub-Saharan African countries, There has been limited interest in investigating its role as a resilience mechanism for communities still practicing it.

The drought-prone area of Sub-Saharan Africa —which stretches from Senegal, through parts of Mali, Burkina Faso, Niger, Nigeria, Chad and Sudan to Eritrea— almost coincides with the polygyny belt—stretching from Senegal to Tanzania. Countries like Burkina Faso, Mali, Senegal, Niger, and Nigeria, all of which are located in the western African part of the drought-prone Sahel region, report the highest proportions of women in polygynous marriages globally.  Rural populations in these countries are highly dependent on rainfed production systems for their livelihoods, making them vulnerable to agro-climatic conditions that predominantly affect rainfed production systems.

Figure 1 shows that polygyny correlates with locations along the Sahel region of Sub-Saharan Africa.


Figure 1: Distribution of Polygyny and Drought in Africa

Distribution of Polygyny and Drought in Africa

Source: Authors’ elaboration based on DHS data (for polygyny) and Dai (2017) (for drought – defined using the Palmer Drought Severity Index (PDSI), estimated as an average over the period 1968-2018).

In our recent study we test the hypothesis that in village economies that lack access to formal risk insurance and labor markets, households rely on traditional institutions such as polygyny — a marriage practice known to undermine development outcomes — to harness their household size and composition as a resilience strategy against drought shocks. Using data from the 2014/15 and 2017/18 Mali LSMS-ISA surveys - collected as part of the Living Standards Measurement Study – Integrated Surveys on Agriculture (LSMS-ISA) initiative - in combination with polygyny data from the Fourth General Census of Population and Housing (2009) and meteorological data, we analyze how polygyny’s interaction with droughts affects crop yields.

Interacting polygyny and drought episodes, we find that polygynous communities are more resilient to drought-induced crop failure. Because polygyny raises fertility, it enables households in drought-prone rural communities to harness the size and composition of the family workforce to their resilience strategies in the context of imperfect rural labor markets and failure of informal risk-sharing mechanisms. In that context, having a large family workforce, well-balanced in age and gender, enables households to diversify crop production and income sources as resilience strategies to counter drought shocks. We find that a year after drought, households living in more polygynous communes are more likely to sell livestock and access credit than those living in less polygynous communes. They are also more likely to hire labor, use improved seeds and chemical inputs, and diversify crop. More importantly, we also find that two years after drought, more families marry off their underage daughters in highly polygynous communes compared to less polygynous ones. This result provides evidence that in bride price rural communities, the common occurrence of covariate income shocks such as droughts increases the value of having multiple daughters, thus incentivizing men to become polygynous.

In that sense, our study is the first to directly link polygyny to child marriage —a phenomenon known to curtail women’s schooling (Field and Ambrus, 2008), impact their reproductive health (Dupre and Meadows, 2007), increase child mortality (de Groot et al., 2018), and overall undermine development outcomes.

As its main takeaway, this study suggests that the high prevalence of polygyny along the Sahel belt in Sub-Saharan Africa may be a response to the scarcity of formal risk management mechanisms and the breakdown of informal risk-sharing mechanisms in rural communities. These problems induce rural households to harness their size and composition as a resilience strategy against the common occurrence of droughts. Given that the literature links polygyny to underdevelopment, including high fertility rates and multidimensional poverty, public interventions aimed at eliminating it should promote the adoption of alternative risk-management mechanisms in these drought-prone communities. Failure to do so may entrench political opposition to enforcing a ban on polygyny and child marriage.


Sylvain Dessy

Professor, Laval University in Quebec, Canada

Luca Tiberti

Professor, Laval University (Canada) and the University of Florence (Italy)

Marco Tiberti

Economist, Living Standards Measurement Study (LSMS), World Bank

David Aime Zoundi

PhD Candidate, Laval University (Canada)

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