Environmental Effect of Biodiesel Energy, Natural Gas, Geopolitical Risk and Economic Policy Uncertainty

The United States, like other developed economies, faces growing pressure to advance sustainable development, especially in line with Sustainable Development Goals (SDGs) 7 and 13. Against this background, this study examines how biodiesel energy consumption influences CO 2 emissions in the United States while accounting for the roles of natural gas consumption, geopolitical risk (GPR) and economic policy uncertainty (EPU). Using monthly data from 1/1985 to 1/12/2025, the study applies recent quantile‐based techniques to capture heterogeneous effects across emission levels and time horizons. The findings indicate that biodiesel consumption increases CO 2 emissions in the short term across most quantiles (0.05–0.90), remains positive in the medium term (0.20–0.95) and continues to exert a positive, though weaker, effect in the long term (0.05–0.80). Natural gas consumption likewise shows a positive effect on CO 2 emissions across nearly all quantiles in the short, medium and long term (0.05–0.95). In contrast, geopolitical risk is largely insignificant in the short and medium term, but in the long term it reduces CO 2 emissions at the 0.30–0.40 quantiles while increasing emissions at the 0.90 quantile. Economic policy uncertainty displays a limited positive effect in the short term at the 0.70 quantile, becomes positive in the medium term across the 0.20–0.50 quantiles and turns negative across all quantiles in the long term (0.05–0.95). These findings provide useful insights for designing environmental and energy policies aimed at reducing emissions while accounting for time‐varying and quantile‐specific effects.