Abstract
Long Term Scenarios (LTSs) can be developed through an iterative process of codesigning with stakeholders and experts to form a joint vision of a development path. Once a roadmap is defined, governments can match financing sources and instruments to deliver the measures and projects defined in the LTS, providing signals to align broader finance flows toward the lower carbon economy. The exercise can increase access to and effectiveness of international climate finance. In the case of Costa Rica, a data-driven, stakeholder-codesigned National Decarbonization Plan (the country's LTS) was launched in 2019. It has been the foundation on which at least US$2.4 billion had been mobilized from international concessional finance sources by the end of 2022. An essential effort underpinning this was a carefully crafted and nationally owned LTS study that leveraged public-good open-models and associated: advanced-schools, communities, principles, and goals. The LTS study's direct cost was less than US$200k.



![Author ORCID: We display the ORCID iD icon alongside authors names on our website to acknowledge that the ORCiD has been authenticated when entered by the user. To view the users ORCiD record click the icon. [opens in a new tab]](https://www.cambridge.org/engage/assets/public/coe/logo/orcid.png)