It’s not enough to blame the consumers’ AC consumption. A bigger shift is necessary, and it begins with policymakers and energy professionals leading the systemic change.

The Current Figures on Urban Heat

Cities often experience temperatures several degrees higher than those in their rural surroundings. Scientists measure this difference at up to 10 to 15° Celsius. This phenomenon — known as the urban heat island (UHI) effect — stems from human-made structures such as concrete buildings and asphalt roads that absorb and reemit solar heat.

The lack of vegetation further limits evapotranspiration, while waste heat from vehicles and industries exacerbates warmth. As over half of the world’s population now resides in cities, addressing cooling needs through clean power solutions without further exacerbating carbon emissions has become a pressing issue.

Solutions Beyond Air Conditioning

Passive cooling and urban design have long helped alleviate heat, but technology integration is now upgrading these approaches through smart networks and renewable energy.

District Cooling

District cooling systems have a long history of use but are increasingly shifting toward more eco-friendly models that use seawater, river water, waste heat or geothermal energy. In the hot and humid city of Hong Kong, seawater from Kowloon Bay is used to cool a massive new business district. This move is expected to reduce carbon emissions by 59,500 tons in just one year, while saving the city 85 million kilowatt-hours of electricity.

Beyond efficiency gains, district cooling systems can also store energy much like a battery. This allows them to absorb cooling when demand is low, then deploy it during peak hours. In doing so, they reduce strain on the power grid and complement variable renewable sources like solar and wind, which fluctuate throughout the day.

Air-Cooled Chillers

For areas without adjacent water bodies to draw from, air-cooled chillers offer a more sustainable alternative to individual AC units for cooling larger buildings. They use the ambient air to dissipate heat and are particularly effective in cities, as they eliminate the need for a constant water supply and tower infrastructure.

Smart Building Envelopes

Thermally efficient building envelopes further complement these infrastructures by minimizing heat ingress. Innovations in insulation materials, glazing and reflective coatings help lower indoor temperatures and cut reliance on mechanical cooling. Retrofitting older buildings with these surface technologies can lead to significant savings, particularly in energy-draining structures with outdated insulation and inefficient HVAC systems.

Electrical Heat Pumps

On the equipment side, electrically driven heat pumps designed for both cooling and heating present a low-emission option. When powered by renewable energy, heat pumps significantly lower carbon footprints compared to conventional HVAC systems. Since 2021, they have met around 10% of global space heating demand — a share that continues to grow.

Nature-Based Solutions

Beyond individual buildings, cities are increasingly turning to nature-based solutions. Urban greening enhances evapotranspiration — nature’s original air conditioner. Plants retain water and release moisture through their leaves, and green roofs and walls amplify this effect by adding natural insulation while blocking direct solar heat through soil and vegetation.

At street level, reflective pavements address the issue from a different angle. They reflect solar radiation into the atmosphere rather than storing it. Research shows that surface temperatures can drop by as much as 11.7° Celsius with heat-reflective coatings. White surfaces deliver the strongest cooling effect, while replacing black pavements with light yellow thin-layer asphalt has achieved reductions of around 11.5 °Celsius.

Color choice, however, introduces trade-offs. Lighter shades tend to lower visual comfort for road users, making red a more practical compromise in many contexts.

Policy Shifts as the Backbone of Clean Cooling Adoption

Technology alone is not enough to shift markets or behaviors. Policies are necessary to spur widespread change. The significant cost savings and emission reduction remain a potential if not enacted.

While many cities around the world are increasingly embracing renewables, numerous metropolitan areas still lack targeted heat mitigation regulations that integrate with clean power goals. Policymakers must design frameworks that incentivize district cooling projects, retrofit programs and energy-efficient building standards to reshape the urban energy profile.Building codes must also mandate or encourage thermal performance measures to strengthen the effectiveness of cooling loads and enforcement rather than dilute it. Governments must ensure these standards reflect regional climates and evolving technologies.

Incentive structures like grants, tax credits and low-interest loans also accelerate stakeholders’ uptake. Programs like demand response and time-of-use tariffs encourage consumers to shift cooling loads to align with renewable generation peaks. This flexibility stabilizes grids and maximizes clean energy utilization.

Coordinated urban planning aligns cooling strategies with transport, housing and infrastructure systems. This collaborative governance brings together public agencies, utilities, communities and industry for integrated action. A decentralized yet connected framework can help manage this complexity so project delivery fits closer to the ground but connects with the broader clean energy agenda.

Finally, funding models need diversification. Beyond federal grants, municipalities must explore partnerships, green bonds and membership-based coalitions to sustain long-term cooling initiatives. Flexible funding mechanisms that empower local innovation prove crucial for adapting solutions to unique urban contexts.

Clean City Cooling as a Collective Enterprise

Cooling cities with clean energy is not merely about switching to better air conditioners. It demands collaboration, with policymakers strengthening the frameworks that communities follow. These solutions must be grounded in the local context while still aligning with the national strategy. Only then will technology become more effective at alleviating heat without contributing to additional warming.