Japan faces the dual challenge of maintaining fiscal sustainability while pursuing an ambitious transition towards a low-carbon economy. Substantial investment in renewable energy, green infrastructure, and low-carbon technology has increased interest in the potential role of public borrowing in financing green transformation. This study examines whether public debt can support Japan's green transition through its relationship with economic growth, CO₂ emissions, and renewable energy. Gross savings and trade openness are included as control variables. The study applies linear autoregressive distributed lag (ARDL) and nonlinear autoregressive distributed lag (NARDL) approaches to assess the long-run relationship and the effects of positive and negative debt changes on economic growth […]