DescriptionThis dissertation research examines carbon neutral pledges made by several nation-states. Several countries have pledged to emit zero net carbon emissions in the near future in response to global climate change. First, this research uses newspaper articles to document which countries have made these pledges. These results show that nine nations have made carbon neutral pledges. Second, this research uses national-level statistics in a fuzzy-set qualitative comparative analysis to identify the common confluence of factors that is present in pledging nations. The results show that pledging nations, compared to non-pledging nations, have smaller populations, more egalitarian class structures, better governance, and more international environmental NGOs. Then, this project includes a case study on Costa Rica’s carbon neutrality pledge. The case study has three parts. First, it provides a historical account of how Costa Rica came to have the institutional profile of a country that makes a carbon neutral pledge. It uses archival research to explain how Costa Rica came to have the small size, egalitarian agricultural economy, good governance, and strong NGO presence that characterize pledging nations. Second, it provides a narrative account of the events that preceded the country’s carbon neutral commitment in February 2007. Archival research and interviews with people in government, industry, science, and civil society are used in this case study. In many ways, Costa Rica’s carbon neutral pledge is latest example of a highly ambitious political action that appeals to people’s values. The carbon neutral pledge reaffirms Costa Rica’s role as country that takes care of its people and takes care of the planet. The third and final section of the case study describes what has happened in Costa Rica since the country made the pledge. While political support for the pledge has in some respects waned since the initial commitment, officials are still committed to the carbon neutral goal and they reaffirmed the commitment in the country’s 2015 Intended Nationally Determined Contribution (INDC) ahead of the 21st meeting of the Conference of the Parties in Paris.