How to keep cool while the world gets hotter

Current Climate and Cooling Paradox

• Recent record-breaking heat waves have affected Canada, the US, Cyprus, India, Iraq, and Kuwait.
• At least 7% of global greenhouse gas emissions stem from cooling systems.
• A feedback loop exists where rising temperatures increase demand for air conditioning (AC), which in turn generates more heat through electricity consumption and gas leaks.
• AC and fans consume approximately 20% of total building electricity, with US AC usage equating to the entire electricity consumption of the African continent.

Environmental Mechanisms of Harm

• Most emissions arise because power grids remain reliant on fossil fuels like coal.
• Refrigeration systems frequently leak hydrofluorocarbons (HFCs), gases thousands of times more potent than carbon dioxide at trapping heat.

Demand Projections and Drivers

• Global AC units in use currently stand at 2 billion, concentrated in a few countries.
• Over 90% of the 3 billion people living in tropical regions do not yet own AC units.
• Urbanization and rising middle-class incomes are predicted to drive demand, with two-thirds of global households expected to have AC by 2050.
• Without policy intervention, cooling-related emissions are projected to rise 90% above 2017 levels by 2050.

Technological Innovations and Limitations

• Stanford spin-out SkyCool is testing passive cooling technology that uses the cold upper atmosphere as a heat sink without electricity input.
• Current high-end innovations risk excluding the world's poorest populations who cannot afford efficient models.
• The transition requires both deploying existing efficient technologies and inventing new ones to allow developing nations to "leapfrog" ahead.

Building Design and Passive Cooling Strategies

• Pre-World War II buildings utilized passive cooling via open windows and natural ventilation; post-war building booms created hermetically sealed skyscrapers requiring massive cooling loads.
• The Global Centre on Adaptation in Rotterdam utilizes a floating office cooled by river water pumped through concrete foundations and cooling ceilings.
• Rotterdam's specific climate (18°C average summer) makes its cooling needs less urgent than in hotter regions.
• In Cairo, eConsult applies traditional techniques like dark entryways, thick walls, and local stone orientation to reduce internal temperatures by 3–4 degrees.
• In Cape Town, painting corrugated iron roofs white reflects sunlight, keeping roofs 30°C cooler and internal temperatures 2–5°C lower than dark-colored roofs.

Urban Policy and Heat Mitigation

• Athens appointed Europe's first chief heat officer, Eleni Miravili, in 2021 to address urban heat islands where land surface temperatures can reach 3.8°C higher than non-urban areas.
• Athens plans to convert streets into green corridors, aiming to reduce local temperatures by 2–2.5°C for pedestrians.
• The city intends to create three green corridors within the next two years while expanding existing urban forests.
• Other cities adopting similar strategies include Paris (targeting 50% planted coverage by 2030), Medellín (green corridors), and Ahmedabad, India (heat action plan).

Future Outlook and Requirements

• Urban heat islands disproportionately affect disadvantaged communities.
• Successful implementation requires unprecedented cooperation between industry, government, finance, and civil society.
• Solutions must be scalable and affordable to apply to all income stratas, avoiding high-end exclusivity.
• Failure to act risks escalating global temperatures and extreme climate phenomena.