<p>Under the Paris Agreement’s ratchet mechanism, countries are expected to regularly strengthen their climate commitments, with 2035 emerging as the next critical milestone. For Korea–one of the world’s largest emitters of CO₂–the central challenge is not only to meet its 2030 nationally determined contribution (NDC), but to define a credible and substantially more ambitious pathway for 2035. In this study, we employ an integrated assessment model to project Korea’s greenhouse-gas emissions trajectory under current policy frameworks, based on the First National Framework Plan for Carbon Neutrality and Green Growth, the Eleventh Basic Plan for Long-term Electricity Supply and Demand, and other officially announced sectoral policies across the economy. We further construct an enhanced policy scenario that reflects highly ambitious yet technically viable and institutionally grounded measures across all major sectors. Our results show that current policies reduce emissions by 35% below net 2018 levels by 2035 (30–41%), even falling short of the 2030 NDC. By contrast, the enhanced scenario achieves a 59% reduction (55–64%) without reliance on international offsets. This deeper reduction is driven by an accelerated coal phase-out, rapid deployment of offshore wind, tighter constraints on lifetime extensions of blast furnace capacity, a ban on new internal combustion engine vehicle sales by 2040, and the gradual replacement of fossil-based heating with heat pumps. These findings provide system-wide evidence that a more ambitious 2035 pathway is feasible when existing policy and institutional constraints are explicitly accounted for, contributing to ongoing discussions on Korea’s post-2030 mitigation strategy.</p>