Effects of marginal CO₂ emissions on life Expectancy: A linear and nonlinear panel analysis of Asean

Abstract

This study investigates the asymmetric effects of marginal carbon dioxide (CO₂) emissions, defined as CO₂ emissions per unit of energy use, on life expectancy in ASEAN countries from 1990 to 2023. Unlike most existing studies that focus on total CO₂ emissions, this paper introduces a novel and policy-relevant indicator that more accurately reflects energy efficiency: marginal CO₂ emissions. Using both linear and nonlinear panel Autoregressive Distributed Lag (ARDL and NARDL) models, the findings reveal that rising marginal CO₂ emissions have a significant negative impact on life expectancy. In contrast, reductions in marginal emissions are associated with improvements in public health, confirming the presence of asymmetric effects. Interestingly, health expenditure and economic expansion exhibit unexpected negative long-term associations with life expectancy, whereas inflation shows contrasting short- and long-term effects. The nonlinear model demonstrates superior explanatory power compared to the linear approach, particularly in capturing these asymmetric dynamics. ASEAN countries are selected due to their rapid economic growth, high environmental vulnerability, and wide heterogeneity in energy efficiency and health systems, making them a critical and timely context for this analysis. Therefore, policymakers should prioritise enhancing energy efficiency and reducing emissions intensity to improve population health outcomes across the region.