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Cities and the IPCC AR6 Synthesis Report

Karolina Eklöw Thu, 23 March 2023

On March 20, the IPCC released the final synthesis of their Sixth Assessment Report (AR6), which took over half a decade to complete. The report brings together the work of over 780 scientists to provide a comprehensive assessment of climate change, its impacts, and what can be done to mitigate it. Here's what's in it for cities. 

Similar to the 2022 IPCC update, this years' report is painting a grim picture of rising emissions risks, but also show what scientists suggests are the best ways forward. 
  • The critical role of cities in achieving deep emissions reductions and advancing climate-resilient development.
  • Policies combined with technology can create social and environmental co-benefits. It highlights the need for public policies to accelerate the global diffusion of mitigation technologies.
  • Financing mechanisms in urban areas must be improved – despite growing public and political awareness of climate impacts and risks, implementation is lagging. 

Cities: observed impacts and changes

Urban areas have already been negatively impacted by climate change, with hot extremes intensifying in cities. Urban infrastructure, including transportation, water, sanitation, and energy systems, have been compromised by extreme and slow-onset events, resulting in economic losses, disruptions of services, and negative impacts on well-being. The urban poor are disproportionally affected. 

Following the global rise of emissions, urban areas too increased their share of emissions, rising from about 62% to 67-72% of the global share between 2015 and 2020. The drivers of urban emissions are complex – they include population size, income, state of urbanization, and urban form (2.1.1 Observed Warming and its Causes).

The report notes that more growing public and political awareness of climate impacts and risks has led to at least 170 countries and many cities including adaptation in their climate policies and planning processes. However, there are still gaps that need to be addressed. A challenge is how to address the lack of resources and funding. 

Policies: effective mitigation that works

The IPCC report shows that there has been a consistent expansion of policies and laws addressing mitigation since AR5. Many regulatory and economic instruments have already been deployed successfully (2.2.2 Mitigation Actions to Date). 

The report emphasizes that combining mitigation policies to shift, induce behavior changes, and create health co-benefits can be effective. Specifically,"measures promoting walkable urban areas combined with electrification and renewable energy can create health co-benefits from cleaner air and enhanced active mobility."


Climate governance enables mitigation by providing an overall direction, setting targets, mainstreaming climate action across policy domains, creating specialized mechanisms to mobilize finance. Effective climate governance builds on engagement with stakeholders, and local communities. The report notes that "climate governance supports mitigation by providing frameworks through which diverse actors interact and a basis for policy development and implementation."


Actions: city climate transitions

The report emphasizes that urban systems are 'critical for achieving deep emission reductions and advancing climate-resilient development.' Two elements are key:
  • Planning: Consider climate change in the planning of settlements and infrastructure.
  • Integrated approach: Inclusive long-term planning that takes an integrated approach to physical, natural, and social infrastructure.

In particular, an integrated approach to planning can accelerate the work across city domains. 

  • Land use: Land use planning to achieve compact urban form, co-location of jobs and housing.
  • Transportation: Supporting public transport and active mobility – e.g., walking and cycling. 
  • Buildings: The efficient design, construction, retrofit, and use of buildings.
  • Consumption: Reducing – and changing – energy and material consumption.
  • Energy: Material substitution and electrification in combination with low-emissions sources.
  • Infrastructure: Green/natural and blue infrastructure supports carbon uptake and storage. It can reduce energy use and risk from extreme events while generating co-benefits for health, well-being, and livelihoods.

Technology: key for co-benefits

Scientists agree that technology innovation can create social and environmental co-benefits. Innovation, adoption, diffusion, and technology transfer in lowering emissions growth must be mainstreamed to reach net zero. 

ClimateView IPCC

The report suggests that public policies such as training and R&D, regulatory and market-based instruments that create incentives and market opportunities, and international cooperation on innovation systems and technology development and transfer, accompanied by capacity building, knowledge sharing, and technical and financial support can accelerate the global diffusion of mitigation technologies, practices, and policies (4.8.3 Technology Innovation, Adoption, Diffusion and Transfer). 


The final synthesis of the IPCC's Sixth Assessment Report has painted a stark picture of the realities of climate change, but lacked the expected media pickup.

Many urban areas have already experienced negative impacts, with infrastructure and vulnerable populations being disproportionately affected. Importantly, the report is highlighting what works. It shows the importance of inclusive long-term city planning, green infrastructure, walking, cycling, and the efficient use of energy and materials. It puts special emphasis on the need for better finance mechanisms. This, in combination with technological innovation, can enable the co-benefits of climate action.


How are leading cities enabling an integrated approach to climate planning with technology? See case studies here.