Climate Finance and Green Bond Evolution

This research considers the case of financing the response to climate change, also known as climate finance, with emphasis on the labelled green bond market; climate finance is an exemplar of policy challenges in which private sector engagement is integral. This research aims to understand the evolution of themes associated with climate finance and green bonds to identify opportunities to enhance public-private cooperation and facilitate policymaking. The research exists at the intersection of policy analysis, climate science, environmental finance, and machine learning, and makes novel contributions across the data, method, and policy areas. The research employs topic modeling approaches in conjunction with sentiment and qualitative analyses on unstructured data to represent discourse surrounding (1) climate finance, and (2) green and climate bonds. The topic models aid in discovering interpretable, low-dimensional subspaces from corporas extracted from LexisNexis using a crowd-sourced search strategy. In the case of understanding the evolution of climate finance, dominant topics in climate finance news headlines are analyzed temporally and geographically. This is done using an unsupervised probabilistic generative topic model, Latent Dirichlet Allocation (LDA), along with an automated process for model selection and hyperparameter optimization. The LDA climate finance results indicate that topics representing the mobilization of capital and collective action are becoming more prevalent and are regarded more positively in recent years — suggesting a strong case for enhanced public-private partnerships. Labelled green bond opportunities are identified through news and blog articles that correspond to green bond sectors. Sector-specific topics are identified with Correlation Explanation (CorEx), an information-theoretic approach to topic modeling. In the semi-supervised version of CorEx, domain knowledge about the sectors is incorporated via topic anchors. The green bond topic results demonstrate the prevalence of certain investment areas, increasing interest that remains historically high, and market opportunities that may exist by focusing on industry and building sectors and consolidating water and pollution-control sectors. Overall, investments in market structuring and frameworks emphasizing monitoring, verification, and reporting will strengthen transparency and consistency, which will leverage the momentum in climate finance and assists in scaling up the green bond market. Furthermore, the methods and approaches herein have broad applicability to other complex policy settings.