Studies Document Rising Urban Heat From Traffic, Transit, and Cooling Use

Three new studies published in the past few weeks measured how human activity adds heat inside cities. One examined traffic emissions, another tracked underground transit temperatures, and a third assessed household air-conditioning use.

U.S. National Center for Atmospheric Research added a traffic heat module to the Community Earth System Model. The module accounts for vehicle type, speed, traffic volume, and time of day. 25 °C respectively. The added warmth was stronger in winter than summer at both locations.

A Northwestern University team analyzed more than 85,000 social-media posts from 2008 to 2024 mentioning heat on the Boston, London, and New York metro systems. They found that each 1 °C rise in outdoor temperature above 10 °C increased thermal complaints by 10 % in Boston, 12 % in New York, and 27 % in London.

The study noted that subsurface temperatures can exceed surface readings; London’s Tube once reached 47 °C.

A Singapore study surveyed 416 households and combined responses with electricity records and spatial heat data. Households with routine air-conditioning access showed lower support for collective heat-mitigation measures such as tree planting. Lead author Natalia Borzino stated that experiencing heat does not automatically translate into lower-energy behavior or stronger collective climate action.

The UK Climate Change Committee separately reported that national infrastructure was built for a climate that no longer exists and recommended scaling cooling measures.