Climate Change and Cities: Second Assessment Report of the Urban Climate Change Research Network

14:00 Tuesday 28 May


Room S8


Chantal Pacteau (France) 1,2; Mattia Leone (Italy) 1,3; Luc Abbadie (France) 1,4; Reimund Schwarze (Germany) 1,5; Nathalie Jean-Baptiste (Germany) 1,5; Martin Lehmann (Denmark) 1,6

1 - UCCRN - Urban Climate Change Research Network; 2 - Centre National de la Recherche Scientifique; 3 - Università di Napoli Federico II - Dipartimento di Architettura; 4 - Université Pierre et Marie Curie - Institute of Ecology and Environmental Sciences; 5 - UFZ - Helmholtz-Zentrum für Umweltforschung; 6 - Aalborg University - Department of Planning

The Urban Climate Change Research Network’s Second Assessment Report on Climate Change in Cities (ARC3.2), edited by C. Rosenzweig, W.D. Solecki, P. Romero-Lankao, S. Mehrotra, S. Dhakal, S.A. Ibrahim and published in early 2018, is the second in a series of global, science-based reports to examine climate risk, adaptation, and mitigation efforts in cities. The book explicitly seeks to explore the implications of changing climatic conditions on critical urban physical and social infrastructure sectors and intersectoral concerns. The primary purpose of ARC3.2 is to inform the development and implementation of effective urban climate change policies, leveraging ongoing and planned investments for populations in cities of developing, emerging, and developed countries. ARC3.2 gives concrete solutions for cities in regard to mitigation and adaptation; urban planning and design; equity and environmental justice; economics, finance, and the private sector; critical urban physical and social sectors such as energy, water, transportation, housing and informal settlements, and solid waste management; and governing carbon and climate in cities. Other key topics include ecosystems and biodiversity, and urban coastal zones. This volume, like its predecessor, will be invaluable for a range of audiences involved with climate change and cities: mayors, city officials and policymakers; urban planners; policymakers charged with developing climate change mitigation and adaptation programs; and a broad spectrum of researchers and advanced students in the environmental sciences.

The session is oriented to disseminate the key messages from ARC3.2 and discuss potential pathways for their implementation, supporting the activities of the UCCRN Regional Hubs in leading a global, sustained, city-focused climate change knowledge and solutions program by strengthening ongoing collaborations and knowledge exchange both for and with cities of various sizes. The focus of the Regional Hubs is to gather and initiate world-class research and apply it to adaptation and mitigation planning. The Hubs operate at the continental-scale and link knowledge to action with tools such as the Case Study Docking Station, and also by working with relevant regional and global actors.

Target audience

This session is meant for city decision-makers and researchers from developing and developed counties willing to advance the knowledge base for mitigation and adaptation solutions, accelerate and improve policy action at the city-level. The participants will engage with the global UCCRN community and have the opportunity of partnering within the many ongoing city projects and collaborations, which include activities with leading global institutions such as African Development Bank, C40, Columbia University Earth Institute, ICLEI, ICMA/CityLinks, Inter-American Development Bank, International Development Research Centre, IPCC, Japan International Cooperation Agency, Nairobi Work Programme, NASA-GISS, Siemens, UNEP, UN-Habitat, UNISDR, and UN-SDSN.

Proposed format for the session

The session will include the official European launch of the book ‘Climate Change and Cities: Second Assessment Report of the Urban Climate Change Research Network’ (Cambridge University Press, 2018), with the presence of a panel of Coordinating and Lead authors (5 minutes).

Seven speakers will present the key cross-cutting topics and highlights from the thematic areas included in the book, which will be discussed with a panel of invited experts (leading researchers, city officials, practitioners) and the audience.

The format include 7 pitch presentation (5 minutes), each followed by an audience discussion (5 minutes).

Conclusions and further research-practice perspectives will be drawn in the final panel discussion (30 minutes).

Contributing Authors abstracts

UCCRN ARC3.2 Pathways to Urban Transformation – C. Pacteau; L. Abbadie

As is now widely recognized, cities can be the main implementers of climate resiliency, adaptation, and mitigation. However, the critical question that ARC3.2 addresses is under what circumstances this advantage can be realized. Cities may not be able to address the challenges and fulfill their climate change leadership potential without transformation.

ARC3.2 synthesizes a large body of studies and city experiences and finds that transformation is essential in order for cities to excel in their role as climate-change leaders. As cities mitigate the causes of climate change and adapt to new climate conditions, profound changes will be required in urban energy, transportation, water use, land use, ecosystems, growth patterns, consumption, and lifestyles. New systems for urban sustainability will need to emerge that encompass more cooperative and integrated urban-rural, peri-urban, and metropolitan regional linkages.

Five pathways to urban transformation emerge throughout ARC3.2, covering key topics such as DRR-CCA integration, adaptive mitigation concepts, co-production of knowledge, community-driven action, institutional capacity-building. They provide a foundational framework for the successful development and implementation of climate action, supporting cities throughout the world in their effort to play a significant role in resilience-based transformation and energy-environmental transition.

Managing Disasters in a Changing Climate – M. Leone

In a changing climate, a new decision-making framework is needed in order to fully manage emerging and increasing risks. This involves a paradigm shift away from impact assessments that focus on single climate hazards based on past events. The new paradigm requires integrated, system-based risk assessments that incorporate current and future hazards throughout entire metropolitan regions.

DRR and CCA are the cornerstones of making cities resilient to a changing climate. Integrating these activities with a city’s development vision requires a new, systems-oriented approach to risk assessments and planning. Moreover, since past events cannot inform decision-makers about emerging and increasing climate risks, systems-based risk assessments must incorporate knowledge about current conditions and future projections across entire metropolitan regions.

A paradigm shift of this magnitude will require decision-makers and stakeholders to increase the capacity of communities and institutions to coordinate, strategize, and implement risk-reduction plans and disaster responses. This is why promoting multi-level, multi-sectoral, and multi-stakeholder integration is so important.

Integrating Mitigation and Adaptation as Win-Win Actions – C. Pacteau

Urban planners and decision-makers need to integrate efforts to mitigate the causes of climate change and adapt to changing climatic conditions. Actions that promote both goals provide win-win solutions. In some cases, however, decision-makers have to negotiate trade-offs and minimize conflicts between competing objectives.

Integrating mitigation and adaptation can help avoid locking a city into counterproductive infrastructure and policies. Therefore, city governments should develop and implement climate action plans early in their administrative terms. These plans should be based on scientific evidence and should integrate mitigation and adaptation across multiple sectors and levels of governance. Plans should clarify short, medium and long-term goals, implementation opportunities, budgets, and concrete measures for assessing progress.

Integrated city climate action plans should include a variety of actions involving energy, transport, waste management, water policies, infrastructure, natural resources, health, and consumption policies, among others in synergistic ways. Because of the comprehensive scope, it is important to clarify the roles and responsibilities of key actors in planning and implementation, coordinating the interactions among the actors during each phase of the process.

Embedding Climate Change in Urban Planning and Design – M. Leone

Urban planning and urban design have a critical role to play in the global response to climate change. Actions that simultaneously reduce greenhouse gas emissions and build resilience to climate risks should be prioritized at all urban scales – metropolitan region, city, district/neighborhood, block, and building – in ways that are responsive to and appropriate for local conditions.

This implies to explore integrated design strategies for creating sustainable and resilient communities that can adapt and thrive in the changing global conditions, meet carbon-reduction goals, provide new public spaces and facilities in relation to community priorities, by configuring or retrofitting compact and mixed-use eco-districts.

The issue of climate resilience in urban areas requires the development of innovative design methods that can handle the complexity of the information needed to guide sustainable urban regeneration and retrofitting strategies, as well as to manage the technological and environmental solutions in a multi-scale and multi-disciplinary perspective. The proposed climate-resilient design principles and methods are process-oriented and focus on sequential and iterative steps bringing to projects’ implementation through knowledge-sharing and co-design approaches that involve different fields of expertise (climate science, health, urban ecology, social studies) and actors (public authorities, local communities, practitioners and business sectors).

Financing Climate Change Solutions in Cities  – R. Schwarze

Since cities are the locus of large and rapid socioeconomic development around the world, economic factors will continue to shape urban responses to climate change. To exploit response opportunities, promote synergies between actions, and reduce conflicts, socio-economic development must be integrated with climate change planning and policies.

Public sector finance can facilitate action, and public resources can be used to generate investment by the private sector. But private sector contributions to mitigation and adaptation should extend beyond financial investment. The private sector should also provide process and product innovation, capacity building, and institutional leadership.

Financial policies must enable local governments to initiate actions that will minimize the costs of climate impacts. For example, the cost of inaction will be very high for cities located along coastlines and inland waterways due to rising sea levels and increasing risks of flooding.

Climate-related policies should also provide with local economic development benefits as cities shift to new infrastructure systems associated with low-carbon development.

Networks of cities play a crucial role in accelerating the diffusion of innovation and best practices, both domestically and internationally. Therefore, cities that initiate actions that lead to domestic and international implementation of nationwide climate change programs should be rewarded.

Housing and Low-Income Communities  – N. Jean-Baptiste

Addressing vulnerability and exposure in the urban housing sector can contribute to the wellbeing of residents. This is especially true in informal settlements, where extreme climate events present the greatest risks. Understanding the impacts of mitigation and adaptation strategies on the housing sector will help decision-makers make choices that improve quality of life and close development and equity gaps in cities.

Informal economic activities are often highly vulnerable to climate impacts, yet they are crucial to economies in low- and middle-income cities. Therefore, direct and indirect costs to the urban poor and their communities should be included in loss and damage assessments in order to accurately reflect the full range of impacts on the most vulnerable residents and the city as a whole.

Efforts to overcome the lack of insurance organization and limited demand for insurance within these communities can help reduce their high reliance on third-party subsidies and enhance climate change resilience.

Retrofits to housing that improve resilience create co-benefits, such as more dignified housing, improvements to health, and enhanced quality of public spaces. Meanwhile, mitigating greenhouse gas emissions in the housing sector can create local jobs in production, operations, and maintenance, especially in low-income countries and informal settlements.

UCCRN Case Study Docking Station  – M. Lehmann

ARC3.2 includes more than 115 city Case Studies across the globe, now searchable in the Case Study Docking Station (, an online database designed to inform both research and practice on climate change and cities by enabling initial scientifically valid cross-case comparisons and analysis across a range of social, biophysical, cultural, economic, and political contexts.

The Case Studies display empirical evidence on what cities are doing on the ground to mitigate and adapt to climate change, across a diverse set of urban challenges and opportunities.

Search criteria include key aspects such as population size (based on metropolitan population), Gross National Income (GNI per capita), Human Development Index (HDI), and coastal classification. Keywords assigned to the Case Studies may include (1) the key hazard (e.g., flood, heat wave, drought), (2) the type of adaptation or mitigation (policy, infrastructure, ecosystem-based, community-based, etc.), (3) the ARC3.2 topic/chapter in which the Case Study is found or to which it relates (e.g., Urban Health, Governance, Equity and Environmental Justice, Urban Ecosystems and Biodiversity, Energy, Transportation, Water Systems, Waste, etc.), and (4) additional keywords selected by the Case Study authors.