This study examines the potential of remittance inflows as a sustainable source of climate action financing in Nigeria’s reform era. Nigeria continues to face a widening climate-financing gap due to constrained fiscal space, declining oil revenues, and persistent external shocks, despite receiving over USD 20 billion annually in remittance inflows. Using macroeconomic quarterly data from 2006Q1 to 2024Q4 and employing the Fourier Autoregressive Distributed Lag (FARDL) framework, the study investigates the short run and long run relationship between remittance inflows and climate financing, proxied by renewable energy consumption. The empirical findings indicate that remittance inflows exert a significant positive effect on climate financing in both the short run and long run, which suggests that remittance inflows contribute to renewable energy adoption and environmentally sustainable investments in Nigeria. Conversely, exchange rate depreciation, inflation pressures, and the COVID-19 pandemic exert significant negative effects on climate financing. This indicates that macroeconomic instability-induced disruptions can increase the cost of green technologies and shift fiscal priorities away from climate-related investment decisions. Policy priorities include the establishment of green remittance investment platforms, policies aimed at maintaining exchange rate and price stability, and stronger integration of diaspora capital into post-reform climate financing frameworks and climate trust funds. These measures are expected to strengthen Nigeria’s capacity to finance climate mitigation and adaptation, and shock responsive resilience, which aligns with Sustainable Development Goals 1, 2, 11, and 13.