Heat from traffic is contributing to rises in city temperatures, study finds
Why it matters: Traffic heat can increase urban air temperatures by up to 0.35°C, pushing human heat stress above dangerous thresholds.
- Scientists at The University of Manchester developed a new physics-based module to directly represent traffic-generated heat within the Community Earth System Model (CESM), a widely used global climate model.
- The new model, published in the Journal of Advances in Modeling Earth Systems, used real-world traffic data from Transport for Greater Manchester (TfGM) and open datasets to validate its findings for Manchester, UK, and Toulouse, France.
- Dr. Zhonghua Zheng, lead author, highlights that while traditional urban heat research focused on buildings and surfaces, their model uniquely simulates how direct heat from vehicle engines, exhausts, and braking interacts with urban environments.
- Traffic heat increased simulated air temperatures by approximately 0.16°C in summer and 0.35°C in winter in Manchester, contributing to human heat stress indicators during the July 2022 UK heat wave and increasing indoor temperatures.
- The model can differentiate between vehicle types (petrol, diesel, hybrid, electric) and respond to changing traffic and weather, allowing scientists to explore how shifts to cleaner transport systems might alter urban heat contributions.
A new study from The University of Manchester reveals that heat generated by urban traffic significantly contributes to rising city temperatures, with a novel physics-based model demonstrating how vehicle emissions measurably warm cities and impact heat distribution. This research, validated with real-world data from Manchester and Toulouse, shows that traffic heat can increase air temperatures by up to 0.35°C and exacerbate human heat stress during extreme events, even influencing indoor temperatures.
