Poster #130 - Cities as Policy Drivers: How Local Climate Policy Adoption Can Drive State Policy Changes

• In Event: Friday Poster Reception

Abstract

Abstract
As federal priorities around climate action fluctuate, subnational actors have emerged as critical drivers for decarbonization in the United States, one of the largest greenhouse gas emitting countries in the world. Cities can play a pivotal role in advancing climate action by acting as laboratories for policy innovation and driving progress toward state and national climate goals. Yet little research has been done to quantify the influence that city climate policies have in moving states towards higher climate ambition.

Methodology: We employ a two-way fixed effects model with panel data spanning 2005–2025. Our primary independent variable is city policy density, which is derived from a database compiled by the authors with over 1,600 climate policies across the 157 highest relative emitting cities across 48 U.S. states. This is paired with state-level policy data from the Climate XChange State Policy Dashboard for our dependent variable. For the regression, we include state and year fixed effects, and control for time-varying confounders that may influence the number of climate policies a state enacts over time, such as state population and population density, state GDP, degree of home rule, and the state’s majority political party. An instrumental variable approach is used to address potential endogeneity concerns between state and city policies. The buildings, transportation, and electricity sectors, which are the most significant economic sectors for climate policies, are also examined to show whether the relationship holds at a more detailed policy level.

Results and Policy Implications: Preliminary results show that the relationship between state policy density and city policy density is positive and statistically significant. This finding is robust to variations in confounding factors, like state population and GDP. This analysis demonstrates that there is a strong relationship between state policies and city policies and highlights the critical role that cities play in bolstering state climate commitments. This emphasizes the role of local-level networks, such as C40 Cities and Climate Mayors, in driving not only high climate ambition at the local level but also supporting more ambitious action at the state level. These results suggest investing in municipal capacity can be a strategic lever for achieving state-wide climate goals and fostering robust emissions pathways that are resilient to federal volatility.

Author

• Stephanie Vo, University of Maryland, College Park
  Presenting Author