As national governments retreat from international climate commitments, regional entities are constructing parallel diplomatic networks that bypass traditional state-level authority structures. The phenomenon demonstrates both the potential and limitations of decentralized climate governance when federal coordination collapses.
Subnational governments—states, provinces, and regional authorities—increasingly occupy space historically reserved for national governments in international climate negotiations. This shift reflects both institutional opportunity and practical necessity. When national administrations withdraw from international climate frameworks or deprioritize emissions reductions, subnational entities possess regulatory authority over significant economic activity within their jurisdictions and can pursue independent climate policies without waiting for federal consensus.
The mechanism operates through bilateral partnerships between regional governments and foreign counterparts, creating networks that function independently of national diplomatic channels. These arrangements formalize cooperation on renewable energy development, emissions trading mechanisms, technology transfer, and joint research initiatives. Unlike international treaties requiring federal ratification, subnational agreements operate through memoranda of understanding that establish cooperative frameworks without constitutional complications.
California has emerged as the most internationally active U.S. state in climate diplomacy, maintaining active partnerships with over a dozen national governments and numerous subnational jurisdictions. The state’s economy—approximately the world’s fourth largest—provides substantial leverage in these negotiations. Partners negotiate access to California’s carbon pricing mechanisms, renewable energy technology, and emissions reduction expertise in exchange for similar cooperation on California’s environmental priorities.
The Challenge of Federal Incoherence: Policy Uncertainty and Market Signals
Subnational climate leadership emerges most prominently during periods of federal policy instability. When the national government withdrew from the Paris Agreement in 2017, state governments responded by establishing the U.S. Climate Alliance—a coalition ultimately representing 24 governors and controlling approximately 60% of U.S. economic output. The coalition’s formation represented an explicit commitment to maintain Paris Agreement-aligned policies regardless of federal policy direction.
This dynamic creates complications for markets and investors. International partners negotiating climate commitments face uncertainty about whether agreements with subnational entities will persist through subsequent federal administrations with different priorities. Businesses investing in emissions reduction infrastructure within particular states require assurance that regulatory frameworks will remain stable. The incoherence between national and subnational policy creates transaction costs that reduce investment efficiency.
Between 2005 and 2022, U.S. Climate Alliance members collectively reduced greenhouse gas emissions by 19 percent while growing collective GDP by 30 percent, demonstrating that climate action and economic growth can occur simultaneously. Yet the inability to coordinate these achievements through national policy mechanisms limits their replicability across non-alliance states and complicates long-term infrastructure planning.
The Limits of Regional Authority: Energy Infrastructure and Supply Chains
Subnational climate policy remains constrained by jurisdictional boundaries. Energy systems, supply chains, and transportation networks cross state and national borders, requiring coordination mechanisms that subnational governments cannot unilaterally establish. A state can mandate zero-emission vehicle deployment, but the manufacturing infrastructure, battery supply chains, and electricity generation facilities serving those vehicles exist across multiple jurisdictions with potentially conflicting policies.
California’s experience illustrates these limitations. The state has mandated transition to zero-emission vehicles and renewable electricity, yet depends on manufacturing occurring in other states with different environmental standards and in countries with minimal climate regulations. The regulatory frameworks California imposes on its own economy cannot directly control upstream production processes occurring elsewhere.
Subnational partnerships partially address these limitations through coordinated policy frameworks. California’s cooperation with Mexico’s Baja California and Sonora states on zero-emission freight corridors and clean ports development extends California’s regulatory authority across borders by creating mutually beneficial arrangements with adjacent jurisdictions. Similar arrangements with international partners negotiate harmonization of standards and mutual recognition of certifications.
Institutional Innovation: Multilevel Governance Networks
The proliferation of subnational climate coalitions reflects institutional innovation in governance structure. The Under2 Coalition—founded by California and Baden-Württemberg—now encompasses over 270 subnational governments committed to keeping global temperature rise below 2 degrees Celsius, representing an alternative institutional architecture operating parallel to official UN climate negotiation frameworks.
These networks create novel accountability mechanisms. Participating governments commit to specific emissions reductions and transparency requirements. Progress monitoring occurs through coalition mechanisms rather than national reporting structures. The arrangements create peer accountability where governments within networks hold each other accountable regardless of national government positions.
However, subnational coalitions lack enforcement authority that national governments possess. If a subnational government fails to meet commitments, consequences operate through reputational damage and potential exclusion from future cooperation rather than through legal mechanisms available in international treaties. This limitation reduces the credibility of commitments made through subnational frameworks.
Economic and Political Determinism: When Scale Determines Capacity
The concentration of international climate diplomacy among wealthy, large-economy subnational governments reflects structural inequalities in capacity and resources. California can establish independent diplomatic relationships because its economic scale justifies sustained international engagement infrastructure. Smaller states and developing country subnational governments lack comparable resources for international diplomacy and depend on national governments to represent their interests.
This dynamic reinforces existing inequality patterns. Wealthy jurisdictions shape international climate policy through subnational networks that exclude less wealthy actors. The frameworks developed through these high-capacity partnerships then diffuse globally, potentially incorporating structural assumptions suited to wealthy economies but poorly adapted to lower-income contexts.
Conclusion: Institutional Complementarity or Structural Fragmentation
Subnational climate diplomacy demonstrates that governance capacity and policy implementation can operate independently of national government positioning. However, the fragmentation of climate policy authority across multiple jurisdictional levels creates coordination inefficiencies and leaves structural climate problems—global energy systems transformation, international supply chain decarbonization—requiring coordination mechanisms that subnational entities cannot independently provide.
Whether subnational networks constitute sustainable alternatives to national policy coordination or merely temporary bridges during periods of federal policy instability remains unclear. The continued viability of subnational climate leadership depends on whether these networks can develop enforcement mechanisms and capacity-building frameworks capable of extending effective climate action beyond wealthy jurisdictions.
Original analysis inspired by content from California Governor’s Office. Additional research and verification conducted through multiple sources.
