on
Urban canals can cut temperatures by more than 2°C during heat waves
New research from The University of Manchester has found that urban canals can cool their immediate surroundings by more than 2°C during heat waves.
The study is published in the journal Nature Communications.
The study, believed to be the first to assess the cooling effects of urban canals on a national scale, examined the urban canal network of Great Britain and Ireland and found that canals reduce surrounding daytime temperatures by an average of around 0.8°C. During heat waves, however, the cooling effect increased to between 1.5°C and 2.3°C.
Researchers say the findings highlight the overlooked role canals could play in climate adaptation as cities become hotter because of climate change.
Using a new energy balance model developed by researchers in the geography, planning and engineering departments, researchers simulated the thermal behavior of more than 2,300 canal sections across Great Britain and Ireland over an entire year.
The researchers found that while canals produce a small warming effect overnight because water retains heat longer than surrounding surfaces, this effect is relatively minor compared with the cooling benefits during the day.
Improving health and well-being
The researchers also assessed how canals affect thermal comfort during hot weather.
Their modeling showed that incorporating the cooling effect of canals reduced the number of hours classified as posing moderate heat risk by around 58%, while hours of high heat risk fell by around 74%. In many locations, canals eliminated periods of extreme heat risk altogether, although the researchers caution that this is partly counterbalanced by rising humidity, which also influences people's comfort during hot weather.
The findings suggest canals could help reduce heat-related illness, improve well-being and encourage people to stay active, walk and bike during hotter weather, in turn providing access to nature and reducing carbon emissions through active transportation.
"As climate change makes heat waves more frequent and intense, cities need every available tool to help people stay safe and comfortable," said lead author Dr. Matt Tomkins. "Our research shows that canals, which were originally built to power the Industrial Revolution, could now play an important role in helping cities adapt to climate change."
"The cooling effect is modest on an average day, but during heat waves it becomes much more significant, reducing nearby temperatures by more than two degrees in some locations. Even relatively small reductions like these can make an important difference to people's health and well-being during periods of extreme heat."
"Urban canals have often been overlooked in discussions about climate resilience, compared with parks and trees. Our findings suggest they should be recognized as part of climate-responsive urban design alongside green spaces, particularly because millions of people already live and work within walking distance of the canal network," Tomkins said.
Supporting climate-resilient cities
The researchers say that alongside urban heat-regulation services, which have been estimated to provide economic benefits of £14.41 million per year by reducing losses in labor productivity caused by hot days, the canals studied could play a role in reducing carbon emissions, both by enabling active transportation during hotter periods and potentially reducing demand for energy-intensive air conditioning.
"Accessible blue and green spaces result in wider health and well-being benefits for society," said co-author Dr. Joanne Tippett. "The cooling that canals offer could help more people stay active and access these spaces even during hot days. This highlights the importance of not only protecting our urban canals, but also considering how to improve signage, access, connectivity with other green infrastructure and wider awareness of these vital networks of urban cooling."
They emphasize that canals are not a complete solution to rising urban temperatures, but argue they should form part of a wider package of climate adaptation measures alongside parks, trees, sustainable drainage and other forms of green and blue infrastructure.
The study also provides a new modeling approach that could be applied more widely to assess how similar waterways contribute to cooling in other cities around the world and complement insights gained from field-based measurements, modeling and satellite-based observations.
Publication details
M. D. Tomkins et al, A national-scale assessment of the impact of canals on urban temperatures, Nature Communications (2026). DOI: 10.1038/s41467-026-75731-0
Who's behind this story?
Swati Mestri holds a bachelor's degree in Electronics Engineering and has worked as a content editor since 2019. She has experience editing research documents across technology, health care, and materials science, and has a particular interest in technology and space. Full profile →
Master's in physics with research experience. Long-time science news enthusiast. Plays key role in Science X's editorial success. Full profile →
Citation: Urban canals can cut temperatures by more than 2°C during heat waves (2026, August 10) retrieved 10 August 2026 from https://phys.org/news/2026-08-urban-canals-temperatures-2c.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.