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Hot enough for you? The Transform Urban Heat Index
Inspired by the Harper’s Index format, the numbers below highlight the scale of the urban heat challenge, and the need to innovate for a cooler future.
Global heat is accelerating
Warmest year on record: 2024¹
Number of heat-related deaths in Europe, 2024: 62,700+³
Estimated annual heat-related deaths worldwide, 2000–2019: 489,000²
Estimated yearly deaths caused by heat stress at work: 18,970
Estimated work-related injuries caused by heat: 22.85 million
Estimated annual productivity loss caused by extreme heat: US$ 2.4 trillion
Cities: heat hits hardest here
Share of world’s population living in cities:
- Today: 55%
- 2050: 68%⁴
Number of city residents expected to face extreme heat by 2050: 1.6 billion
Temperature gap between poorest and wealthiest neighborhoods in some cities: 2.2°C (4°F)⁷
Projected rise in number of urban poor exposed to dangerous heat by 2050: 700%⁸
Cooling: a growing strain on energy systems
Air conditioners in use worldwide:
- Today: ~2 billion
- 2050: ~5.5 billion⁹
Share of global electricity used to cool buildings: 20%¹⁰
Share of global greenhouse gas emissions from cooling: 3–4%¹¹
Projected rise in electricity use for air-conditioning by 2050: 200% (3× current levels)¹²
Estimated share of peak electricity load from AC and electric fans by 2050: 30–50%¹³
Reduction in cooling energy use from cool roofs: Up to 27%¹⁴
Telecom & data centers: heat behind the cloud
Share of global electricity used by telecom operators (2023): 1%¹⁵
Share of power consumption used for cooling at an average mobile base station: 50%¹⁶
Reduction in mobile operator emissions, 2019–2023, despite data traffic quadrupling: 8%¹⁷
Share of data center electricity used for cooling: Up to 40%¹⁸
Share of global electricity used by data centers:
- 2024: ~1.5%
- 2030: ~3% (driven by AI growth)¹⁹
Projected growth in data center electricity demand, 2024–2030: 2× (~15% per year)²⁰
Electricity consumption of largest AI-focused data centers under construction: Equivalent to ~2 million households²¹
Data center electricity use by 2030 compared to today: More than double (~945 TWh)²²
Emissions from data center electricity use by 2035: 300 Mt CO₂ (Base Case)²³
Digital tech: part of the solution
Potential global reduction in energy-related emissions enabled by AI: Up to 5%²⁴
Potential energy-use reduction enabled by efficient digital technologies: Up to 35%²⁵
Sources: ¹ World Meteorological Organization; ² World Health Organization; ³ Barcelona Institute for Global Health; ⁴ United Nations World Urbanization Prospects; ⁵ IIED; ⁶ PreventionWeb / Global Heat Atlas; ⁷ National Library of Medicine (PMC); ⁸ World Bank; ⁹ IEA; ¹⁰ IEA; ¹¹ United Nations; ¹² IEA; ¹³ World Bank; ¹⁴ U.S. EPA; ¹⁵ GSMA; ¹⁶ NGMN Alliance; ¹⁷ GSMA; ¹⁸ Deloitte Brazil; ¹⁹ IEA; ²⁰ IEA; ²¹ IEA; ²² IEA; ²³ IEA; ²⁴ IEA; ²⁵ Telefónica
