For the past two decades, international climate policy has been handled as a matter for State to State deliberation. Non-state actors have played at best marginal roles in making and implementing international policy. This paper argues that climate change remains an intractable transnational problem because State to State deliberations failed to acknowledge that both climate mitigation and adaptation require ongoing collaborative governance with non-State actors to shift normative behavior. This paper proposes experimenting with scaling up Dutch environmental covenants as an international co-regulation strategy to improve both the legitimacy and accountability of international climate governance. This paper specifically proposes in the context of climate change mitigation implementing a co-regulatory approach through a combination of State-approved emission targets and binding individual firm environmental agreements.