Columbia Experts and Rio Leaders Lead Urban Climate Adaptation Discussions at the U20 Summit

Climate Hub Rio played a significant role at the Urban 20 Summit (U20 Summit) in Rio de Janeiro, an international event that brought together city leaders held in the lead-up to the G20 Leaders’ Summit.  Serving as a dynamic platform for dialogue and collaboration, the U20 Summit gathered representatives from global urban centers and renowned scholars to discuss pressing issues such as urban resilience, climate finance, and sustainable development. 

The summit's agenda included a series of thought-provoking panels, including four organized by Climate Hub Rio. Each panel focused on critical aspects of urban climate action, from exploring financial mechanisms that enable cities to achieve ambitious climate goals to discussing governance and policy strategies for sustainable urban development. These discussions outlined a roadmap for building resilient, net-zero cities. Notable highlights included the launch of the book “Sustainable Urban Development: Governance, Finance, and Policy” in partnership with the Brazilian Center for International Relations (CEBRI), as well as a dedicated session on enhancing urban climate resilience leadership in Rio de Janeiro, which brought together local and global experts to share insights and strategies.

Urban Climate Financing and Resilience: Cities Leading the Change 

The panel “Climate Financing and Urban Resilience: Cities Leading the Change”, held on the first day of the event, gathered experts, policymakers, and city leaders to discuss strategies for empowering municipalities in their climate adaptation and mitigation efforts. Organized to foster urban resilience, the discussion highlighted the dual role of cities as both major sites affected by climate impacts and key drivers of innovative solutions. 

Giulia Spiess, Program Coordinator at the Wilson Center, opened the session by emphasizing the critical role of cities in addressing climate change. With more than half the world's population residing in urban areas, cities bear significant responsibility but face considerable financial and operational constraints as subnational entities. Spiess pointed to the importance of fostering intercity cooperation and building capacity, particularly for medium and smaller cities, to address these challenges.

Feliciano Guimarães, Academic Director at CEBRI and professor at the University of São Paulo (USP), underlined the diplomatic significance of events like the U20. He stressed that urban resilience must become a national priority, given its essential role in addressing the climate crisis. 

Thomas Trebat, Founding Director of the Columbia Global Center Rio and the Climate Hub, echoed these sentiments, underscoring that urban areas are critical arenas for climate action. He cited Rio de Janeiro and São Paulo as models for the Global South, noting that while private-sector involvement and international funds are vital, cities must first leverage local fiscal resources and foster collaboration between governments, scientists, and communities. 

Valerie Plante, Mayor of Montreal, shared insights on urban leadership amidst climate-related disasters during her keynote speech. She highlighted the anxiety such events generate among residents, which creates pressure for swift governmental responses. Plante emphasized the need for bold but well-communicated policies, citing Montreal's innovative "biker highway" as an example of transformative urban initiatives that can gain public support when properly implemented, despite facing initial resistance. She also called for collective action, underlining the need to engage the private sector, academic institutions, and vulnerable communities.

Marina Caetano from Talanoa Institute, an NGO dedicated to supporting Brazil in implementing public policies that positively impact people and the planet, moderated the panel and guided the discussion toward practical implementation. She noted that while data and diagnostics are plentiful, the focus now must shift to actionable solutions. 

Adalberto Maluf, Brazil’s Secretary for Urban Environment and Environmental Quality, presented the "Green Resilient Cities" plan, which places municipalities at the center of Brazil’s ecological transition. He stressed the importance of integrating public policies with institutional financial support and making urban projects appealing to private-sector investment. 

Federica Ranghieri, Program Leader for Sustainable Development for Egypt, Yemen, and Djibouti at the World Bank, highlighted the financial challenges cities face in climate adaptation. With urban climate-related disaster costs estimated to rise to $515 billion annually by 2030, Ranghieri urged local governments to address financing gaps through tools like green bonds and climate funds while enhancing municipal capacity for long-term investments. 

Mark Watts, Executive Director of C40 Cities, stressed the need for proactive disaster preparedness, robust early warning systems, and green financing. Highlighting Brazil's leadership, he referenced São Paulo’s expanded green spaces and Rio’s integrated emergency operations center as exemplary models. 

Maria Dombrov, Associate Researcher at NASA Goddard Institute for Space Studies and Columbia University's Center for Climate Systems Research, concluded the session by showcasing ARC.3.3, an upcoming urban resilience-focused report. She emphasized its potential to influence the Intergovernmental Panel on Climate Change (IPCC) findings and announced ongoing projects aimed at positioning Rio de Janeiro as a global leader in urban climate resilience. 

The panel demonstrated that while cities are on the frontline of climate impacts, they are also powerful agents of change. Success hinges on bridging financing gaps, fostering collaboration, and advancing actionable, community-focused policies.

Urban Sustainable Development: Governance, Finance and Politics

On the second day, the panel “Urban Sustainable Development: Governance, Finance and Politics” provided a comprehensive discussion on the challenges and opportunities for cities to drive sustainable development. The session also marked the launch of a book of the same title, developed through a partnership between the Columbia Climate Hub, the Brazilian Center for International Relations (CEBRI), and the Municipality of Rio de Janeiro City Hall. The book features contributions from numerous Columbia University researchers and experts from different regions around the world.

Fernando Straface, Director General at the Center for International Strategies at Universidad Austral, highlighted U20’s critical role since its inception in 2018, during Argentina's G20 presidency. He emphasized the importance of fostering a dialogue between global city mayors and national leaders on urban-centered global challenges, such as climate change and migration. Straface stressed that cities must become specialized agents in addressing climate imperatives, particularly in the context of vulnerable populations. However, he pointed out that current fiscal and intergovernmental relations hinder cities from accessing international financial institutions, designed primarily to work with nation-states.

HE Fahd Al-Rasheed, advisor to the General Secretariat of the Saudi Council of Ministers, underscored the complexity of cities, as they generate 90% of global GDP while contributing to 70% of emissions. He called for well-prepared urban leaders with technical, political, and executive expertise, arguing that leadership development is essential given the expected growth of urban governance roles. Al-Rasheed advocated for collaboration among business leaders, intellectuals, and researchers to effectively address urban challenges.

Former Mayor of Quito, Mauricio Rodas, discussed the disconnect between global financial architecture and urban needs. He noted that nearly half of the world’s countries do not allow cities to borrow funds, creating barriers to financing sustainable urban projects. Rodas introduced the Green Cities Guarantee Fund as an innovative mechanism to address these issues, enabling cities to bypass national restrictions and secure financing through utilities and private-sector partnerships.

Rebecca Chavez, President and CEO of the Inter-American Dialogue, focused on the gender digital divide, emphasizing that subnational actors play a key role in bridging gaps in digital inclusion. She outlined barriers faced by women, such as limited internet access, lack of digital skills, and caregiving responsibilities. Chavez highlighted Mexico City's investment in Wi-Fi hotspots as an example of progressive urban policies to empower women digitally.

Columbia Climate School scholars brought a wealth of insights to the discussion. Paul Gallay stressed the importance of community engagement in urban resilience planning, advocating for transparency and long-term collaboration between governments and local populations. Amy Campbell warned of escalating climate risks, urging immediate investment in adaptation strategies to mitigate non-linear, compounding disasters. Andrew Kruczkiewicz emphasized the challenge of having "too much data, too little time," stressing the need to prioritize and interpret data for climate resilience. He pointed out the importance of determining which data to trust and identifying decision-makers to set priorities. Using Rio de Janeiro as an example, he advocated for the integration of data to drive practical urban planning solutions.

The session concluded with recommendations for G20 leaders, including advancing urban finance reform, funding digital inclusion, and promoting community leadership to work in tandem with government initiatives. These reflections solidified the panel’s and the book’s message: sustainable urban development requires innovative governance, inclusive financing, and collaborative leadership.

Enhancing Urban Climate Resilience Leadership in Rio de Janeiro

In the following session, the panel “Enhancing Urban Climate Resilience Leadership in Rio de Janeiro” underscored the city’s pivotal role in tackling climate challenges. This event was part of a project funded by Climate Hub Rio and led by Cynthia Rosenzweig, a climatologist at NASA’s Goddard Institute for Space Studies and Columbia University. The session showcased collaborative approaches to enhancing resilience. 

Thomas Trebat, founding director of the Columbia Global Center in Rio, opened the discussion by highlighting Rio's opportunity to demonstrate how subnational governments can drive climate action through science-backed public-private partnerships, such as the Climate Hub. Moderated by Maria Dombrov, Associate Researcher at NASA Goddard Institute for Space Studies and Columbia University's Center for Climate Systems Research, the panel explored solutions tailored to Rio’s unique challenges.

Cynthia Rosenzweig participated via videoconference and presented the work of the Urban Climate Change Research Network (UCCRN). She emphasized Rio’s potential as a global model for resilience, advocating for neighborhood-level urban planning and the development of sustainable corridors. Using data on rising temperatures, uncertain precipitation, and coastal flooding, she underscored the urgency of preparation for extreme events.

Felipe Mandarino, from the Pereira Passos Institute, detailed climate action priorities, including heatwaves, landslides, floods, and sea-level rise, particularly in vulnerable inland areas. Marcus Belchior, head of Rio de Janeiro’s Operations and Resilience Center, stressed that resilience policies must be based on scientific evidence, rather than assumptions. He highlighted partnerships with academic institutions and data-driven infrastructure projects, such as Praça da Bandeira’s flood reservoir and Guaratiba’s dikes, as lifesaving measures.

Daniel Mancebo, General Coordinator of Rio’s Planning Office and a participant in Climate Hub’s climate leadership exchange program shared local initiatives like sustainable corridors and localized pilot projects aimed at addressing urban challenges while promoting climate justice. Maria Fernanda Lemos, professor at PUC and IPCC member, underscored the importance of participatory processes to address vulnerabilities tied to socioeconomic inequalities. Susannah Kagan from UCCRN highlighted the two-way relationship between science and policymaking to bridge gaps and refine solutions.

Daniel Zarrilli, Columbia University’s Chief Climate & Sustainability Officer, concluded the session by drawing on New York City’s climate efforts as a model for Rio. He expressed optimism about the city’s potential to forge a resilient path forward through collaboration and innovation.

The panel affirmed Rio’s leadership in urban climate resilience by leveraging science, partnerships, and local engagement to address pressing challenges.

Cities Summit on Urban Planning and Sustainability: Climate Budget, Financing, and Carbon Instruments

Finally, the “Urban Planning and Sustainability: Climate Budget, Financing, and Carbon Instruments” session, moderated by Thomas Trebat, brought together the experiences of Rio de Janeiro, Fortaleza, and Tshwane (South Africa) to enhance the discussion through shared know-how on the implementation of urban climate strategies. Trebat emphasized that Columbia University’s contributions, through data and scientific support, are crucial for local decision-making in cities, citing the specific case of Rio. He underscored the importance of identifying budget allocations and financing mechanisms driven by local stakeholders who are directly engaged in their cities’ development.

Elcio Batista, the Deputy Mayor of Fortaleza, shared the city's approach to addressing social inequality, noting that many challenges within Fortaleza are localized. The city’s long-term strategy focuses on continuity in governance, especially in tackling climate change, and includes the creation of a city master plan for 2040 and the adoption of a four-year Pluriannual Plan. He emphasized the necessity of an integrated planning process and the critical role of data as a starting point for public policy. Batista pointed out the importance of structured project designs to attract financing, citing the expansion of Fortaleza’s cycling infrastructure and the transformation of a former landfill into one of the city's most frequented parks as key examples of sustainable urban innovation.

Daniel Mancebo, a leading figure in Rio de Janeiro's climate governance, provided an overview of the city's concrete steps toward implementing climate actions. He discussed the importance of aligning Rio’s budget with the city's carbon-neutrality strategy, noting that Rio is the only city in Latin America in the pioneering C40 Climate Budget group. Mancebo highlighted the institutionalization of Rio’s sustainable development plan, which links climate action with economic development and equity, ensuring that climate goals are integrated into the city's long-term strategic and financial planning.

Dolly Mafa, Sustainability Specialist for the City of Tshwane, South Africa, presented the city’s ambition to establish its first climate budget in 2024. Mafa explained how Tshwane is integrating climate considerations into its capital planning system, emphasizing inclusive governance and cross-departmental collaboration. By focusing on reducing carbon emissions while building resilience, Tshwane aims to foster more sustainable urban growth. She stressed the need for institutional actions and an integrated approach, including climate budgeting and stakeholder engagement, to ensure that the city can balance both climate action and development priorities.

Andrea Fernandez, Director of Climate Finance, Knowledge, and Partnerships at C40, wrapped up the session by discussing the importance of linking climate budgeting to financing. Fernandez outlined the climate budgeting process, which emphasizes transparency, accountability, and informed decision-making. She advocated for a continuous cycle of planning, integration, implementation, and learning, ensuring that cities’ budgets align with their climate action goals. She also underscored the importance of prioritizing climate projects and allocating resources efficiently to achieve immediate benefits, such as improved public health and reduced emissions, while sending a strong message to national governments, investors, and rating agencies about cities’ commitment to effectively managing climate change.