Replication Data for: Why Cities Join Environmental Transnational Municipal Networks: Political Ideology, Geographic Vulnerability, and the Limits of Climate Risk

This dataset supports the analysis in \"Why Cities Join Environmental Transnational Municipal Networks: Political Ideology, Geographic Vulnerability, and the Limits of Climate Risk.\" It comprises two cross-sectional datasets covering 109 U.S. cities and 77 South Korean cities, capturing membership in three major Environmental Transnational Municipal Networks (ETMNs)—ICLEI–Local Governments for Sustainability, the Global Covenant of Mayors for Climate and Energy (GCoM), and C40 Cities—as of 2023.The datasets were compiled from multiple sources including official ETMN membership lists, the Notre Dame Global Adaptation Initiative (ND-GAIN) Country Index, the Simple Maps World Cities Database, the U.S. Census Bureau, Statistics Korea, and Local Finance 365. Mayoral party affiliations for U.S. cities were identified through official government websites and verified through secondary sources; South Korean mayoral affiliations were identified through Naver.com and supplemented by Wikipedia.