Cities can drastically curb emissions as clean technologies become cheaper, according to a new report from C40 Cities, Arup and Green Futures Solutions.
Launched as the C40 World Mayors Summit takes place in Rio de Janeiro (3-5 November 2025), the "Accelerating Urban Climate Action" guide shows how cities can become 'enablers' of positive climate tipping points.
Thanks to national policies and investment, clean technologies such as electric vehicles and heat pumps are now set to become as cheap as their fossil fuel equivalents. This unlocks promising solutions to the two leading sources of urban emissions: transport and buildings, which account for 79% of potential emissions savings across the world's cities.
Based on an analysis of leading cities, the report focuses on how city decision-makers can accelerate the adoption of EVs and HPs and trigger positive tipping points by:
- Understanding the city's unique role. As clean technologies approach cost parity, the policy focus shifts from national-level affordability to city-level action. Cities can leverage their direct control over infrastructure, planning, and local regulations to drive accessibility and attractiveness, the key levers they control.
- Deploying proven policy strategies: As leading cities have shown, an integrated 'mix' of policies works best: first 'pulling' the market with incentives and leading by example, then 'pushing' out fossil fuels with pre-announced regulations, all while using key city levers like zoning, building codes, and fleet electrification. To do so, cities can utilise key regulatory levers as well as their unique powers as innovators, advocates, and community partners to pull and push markets.
- Adapting over time and maximising collective impact: The report explains how city strategies must evolve as markets mature. It also demonstrates how collective action among cities can create powerful spillover effects, shaping global markets and driving down technology costs for everyone.
Markus Berensson, Head of Mitigation Research at C40 Cities, said: "As clean tech gets cheaper, city action on accessibility and attractiveness (infrastructure, local regulations) becomes essential to trigger tipping points since local governments control vital levers like urban planning, building codes, public fleets, and Low Emission Zones to create early demand and de-risk the transition."
Dr Steve Smith, Impact Fellow at Green Futures Solutions, University of Exeter, said: ""This strategic guide to city-level acceleration of action – by triggering positive tipping points in the adoption of electric vehicles and heat pumps - is exactly the kind of evidence-based hope the world needs in this decisive decade. People are moved to act when they feel hope and agency to turn all the perils of climate risk into the possibilities for the future - and action at the city level is where these possibilities are being made tangible."
