COP30 and the Nature-Climate Nexus: Unlocking the Potential of Subnational Governments

The road to COP30 comes after a series of summits that gradually expanded the climate agenda. COP28 in Dubai began formally linking climate and biodiversity, and COP29 in Baku focused on shaping climate finance. Now, COP30 in Belém, scheduled for November 10–21, 2025, offers a chance to move beyond policy statements to action, potentially the first climate COP where integration of climate and nature is operationalized at scale.

As COP30 approaches in Brazil’s Pará state, the spotlight turns to the Amazon, a region whose forests, rivers, and wetlands are central to global climate stability. This is the first UN climate summit to take place in the heart of the rainforest, offering not just symbolic significance but a real-world test of how climate and biodiversity action can be integrated at scale. The summit’s location underscores the stakes: the future of the Amazon is inseparable from the success of global climate and conservation goals.

This setting highlights the urgency of linking climate action with nature conservation, while also posing a pressing challenge: who will implement solutions that must span ecosystems, jurisdictions, and sectors? The answer increasingly points to subnational governments, i.e., territorial units between national and municipal levels, including states, provinces, and regional authorities. Despite their pivotal position at the intersection of ecological realities and human settlements, these actors remain under-recognized, yet they are essential for translating the nature–climate nexus from abstract concept into practical, on-the-ground outcomes.

The Amazon Setting: More Than Symbolism

The Amazon basin stores roughly 150–200 billion tons of carbon and regulates global rainfall patterns, yet deforestation and degradation are pushing it toward a tipping point where parts could shift from absorbing CO₂ to releasing it. This ecological threshold is not an abstract concern, it directly affects global temperature targets, food systems, and hydrological stability across continents. Hosting COP30 here means every negotiation will unfold amid the tangible stakes of resilience and vulnerability.

The Amazon is a complex governance mosaic spanning nine countries, encompassing approximately 20 administrative regions, over 760 municipalities in Brazil alone, and more than 3,000 Indigenous territories, alongside federal agencies and private lands. The scale and diversity of governance in the Amazon highlight the challenges of coordination across different levels, from highly localized municipalities to larger state governments. Understanding the relative roles and capacities of these levels is crucial: municipalities, though close to local realities, are numerous and fragmented; states, in contrast, are large and politically distant; and subnational governments, on the other hand, operate at an intermediate scale, covering functional ecological units while remaining connected to local conditions.

In this sense, the Amazon embodies both the symbolic urgency of climate and biodiversity agendas and the practical governance challenge of translating ambition into action. Its scale and complexity implicitly point to well-positioned levels suited to this task: those who operate across municipalities yet are grounded in territorial realities, those that hold the key to making nature–climate solutions work on the ground.

Understanding the Nature–Climate Nexus

The nature–climate nexus captures a simple but powerful idea: climate change and biodiversity are deeply intertwined. Healthy ecosystems don’t just store carbon, they shield communities from floods, droughts, and heatwaves. At the same time, stable climate conditions are essential for these ecosystems to survive. Forests, wetlands, mangroves, and grasslands are not just “nice-to-haves”; they are frontline defenders in the fight against climate change.

Yet, in practice, climate and biodiversity have often been treated as separate tracks. Climate policy targets emissions and energy transitions. Biodiversity policy focuses on species and habitats. The result? Projects that succeed in one domain can fail in the other. A renewable energy installation may cut emissions but damage local ecosystems. A conservation project may protect species, only to be undone by rising temperatures or changing rainfall patterns.

The conversation is shifting. Scientific evidence and statements like the COP28 Joint Statement on Climate, Nature and People are pushing for integration. A key tool in this shift is nature-based solutions (NbS), i.e., actions that work with ecosystems to simultaneously address climate and biodiversity goals. This includes forest restoration, watershed protection, and coastal zone management.

Nevertheless, the operational question remains: who governs at the scales where climate and biodiversity intersect? This question frames the challenge of turning the nature–climate nexus from a concept into real-world results.

The Governance Challenge: Why Subnational Governments Matter

Nature-based climate solutions rarely align neatly with municipal boundaries or national policy frameworks. They occur across rural–urban gradients, ecosystem continuums, and multiple administrative jurisdictions. Local governments may be closely connected to local realities, but often lack the capacity to manage entire landscapes. States can mobilize resources at a large scale but may struggle to adapt policies to local ecological variability. Subnational governments, by bridging these gaps, can integrate local knowledge, coordinate actions across jurisdictions, and implement strategies that address nature and climate objectives effectively.

While much scholarship focuses on nation-states and urban networks, subnational governments remain an understudied tier in this domain, despite being structurally positioned to make or break the implementation of nature–climate solutions. Their role is critical because they occupy the “middle ground” where ecosystems and human settlements intersect. Three key factors justify their role

• The Functional Imperative: While national policies lack the spatial precision for ecosystem management, the limited geographical limitations of cities lack jurisdiction over the landscapes where most nature-based solutions occur. Subnational governments can govern across a wide administrative and geographical boundaries while keeping ecosystem integrity intact. Without their coordination, global commitments and urban initiatives cannot reach the ecological scales where interventions matter most.
• Unique Positioning: They hold cross-jurisdictional authority to coordinate land-use decisions across multiple municipalities within ecosystem boundaries; integrated sectoral authority to align agriculture, forestry, and water management; and rural–urban planning jurisdiction to manage landscape gradients where nature-based solutions must operate.
• Finance as a Scaling Tool: New instruments like the TFFF and CBD COP16 biodiversity funding targets increasingly require landscape-scale accountability. Subnational governments are the best-placed actors to link these financial flows to measurable ecosystem outcomes, creating frameworks that integrate rural, peri-urban, and natural areas, something neither national nor municipal governments are designed to do.

Examples already exist. The subnational government of Pará’s has piloted jurisdictional REDD+ programs that integrate municipal forest management with state-level carbon accounting. Likewise, Quebec has aligned climate and biodiversity strategies through regional land-use planning. These illustrate what becomes possible when subnational authorities are empowered to act at the nexus.

Strategic Openings for COP30: From Opportunity to Action
The convergence of Amazonian symbolism on the nature–climate nexus and its governance challenge sets the stage for COP30 to be more than a symbolic summit. It presents a unique chance to align political momentum with the operational capacities of the subnational level. The Amazon illustrates both the urgency of linking climate and biodiversity and the governance gaps that stand in the way, while subnational governments emerge as strategically positioned to bridge those gaps.

Against this backdrop, COP30 in Belém offers a timely opportunity to translate these insights into action. By channeling finance at the territorial scale, COP30 could enable projects that match ecological boundaries rather than political ones, such as cross-municipal watershed restoration or coordinated agroecological transitions that deliver both climate and biodiversity gains. Supporting integrated monitoring and reporting would give subnational authorities the tools to track carbon storage, biodiversity trends, and ecosystem services together, making international finance flows more transparent and accountable. And by recognizing the relevance of subnational authorities in UNFCCC processes, the summit could align governance structures with the very scales where nature-based solutions must operate. Taken together, these steps would move the nature–climate nexus from abstract ambition toward practical, implementable action.

If COP30 in Belém can begin aligning governance with ecological realities, it could influence not only the future of the Amazon but also set a precedent for other biodiversity-rich regions where climate and nature goals depend on territorial action. The road from rhetoric to results runs through these territories, and COP30 may mark the moment when that recognition becomes the basis for global practice.