Agricultural methane-environment thesis in poor African countries: which environmental curve is valid?

This study attempts to empirically establish the environmental curve that is applicable to the nexus between agricultural methane emissions and the environment in poor sub-Saharan African countries. The empirical analysis is conducted on annual data spanning 1990-2019 for 25 sub-Saharan African countries classified as heavily indebted by the International Monetary Fund. Continuously updated fully modified estimation and bootstrap panel causality testing are employed for the analysis. The results from the continuously updated fully modified estimation show that the coefficients for per-capita income and its quadratic form are - 0.446 and 0.011, respectively. This indicates that there is a U-shaped relationship between agricultural methane emissions and per-capita income in these poor sub-Saharan African countries. This U-shaped relationship is indicative of the environmental Brundtland curve. As suggested by the environmental Brundtland curve, this study shows that at lower levels of per-capita income, agricultural methane emissions are usually high in sub-Saharan Africa. As income improves, emissions gradually decline until a turning point beyond which further improvements in income again begin to aggravate agricultural methane emissions. It is thus concluded on this basis that the nature of the environmental curve reflecting the income-agricultural methane emissions nexus is a function of the economic status of the country or region under consideration. Moreover, the bootstrap panel causality results further show that feedback causal relations are predominant across countries in the link between per-capita income and agricultural methane emissions. This outcome is indicative of a vicious cycle in which poverty aggravates pollution, and pollution in turn further aggravates poverty. It also buttresses the claim that the poor are both perpetrators and victims of environmental degradation. The findings emphasize the need for a green growth path in sub-Saharan Africa that is capable of preventing the return to a positive relationship between income and emissions beyond the turning point in the Brundtland curve.