Income inequality and economic policy uncertainty as dual threats to environmental quality for achieving sustainable development goals

Economies facing persistent income inequalities and low environmental quality find it more difficult to achieve the Sustainable Development Goals (SDGs). The literature is enriched with ecological studies and the factors related to this, but the impact of income inequalities in the sphere of uncertain economic policy remains underexplored. Keeping in view the significance of the nexus between income inequality and environmental quality, the present study looks into certain conditions prevailing in the fast-growing BRICS economies comprising Brazil, Russia, India, China, and South Africa, over the period from 1990 to 2020. The study constructed two relevant models that examine the effects of income inequality (IIE) and the combined effect of income inequality and economic policy uncertainty (IIE × EPU) on CO2 emissions, with renewable energy consumption (REC) and economic growth (EG) as controlled determinants. To assess the association between the study variables, the study used the panel quantile regression (PQR) technique, following the features of the data. The conclusions reached indicated that higher IIE leads to a rise in CO2 emissions across all quantiles (0.10–0.90) in both models, ranging from 0.409% to 0.679%, with high intensity in the lower quantiles. Interestingly, combining CO2 emissions with economic policy uncertainty offsets the deteriorating impact of IIE on the environmental quality, ranging from -0.094% to -0.065% across all the quantiles except at the lower quantile (0.10) and upper quantile (0.90). Moreover, the connections between EG and CO2 emissions do not support the presence of the EKC hypothesis in these economies. Keeping in view the outcomes, the study also crafted certain policy implications that align the study with several SDGs, like SDG 07, enhancing the use of affordable and clean energy, SDG 10, aiming at controlling inequalities in the societies, and SDG 13, focusing on climate action.