Urban canals can cut temperatures by more than 2°C during heat waves

A new study reveals that urban canals in Great Britain and Ireland significantly cool their immediate surroundings during heatwaves, offering a vital resource for communities facing increasingly severe heat conditions. Researchers found that canals can reduce local temperatures by more than 2°C during extreme heat events, with the cooling effect extending up to 50 meters from the water’s edge. The study, conducted by scientists at the University of Manchester, analyzed the thermal impact of canals across the region, highlighting their potential role in climate adaptation strategies for cities grappling with rising temperatures. The research team used a sophisticated energy balance model to simulate the interaction between canal water temperatures and the surrounding air over the course of an entire year. By examining data from 68 canals, the study mapped the cooling effects across different times of the day and seasons. It found that during spring and early summer, canals cooled their surroundings by approximately −1.2°C to −1.4°C, while during heatwaves, the cooling effect reached more than 2°C. Although canals slightly warmed their environments at night, by about 0.2°C, the overall cooling benefits far outweighed this minimal warming. The study underscores the broader implications of urban canals beyond their historical significance as industrial arteries. With nearly 6.2 million residents living within a one-kilometer radius of urban canals, the cooling effect directly impacts public health and well-being. The research suggests that canals can reduce the number of hours classified as posing moderate or high heat risk by up to 74%, effectively eliminating periods of extreme heat risk in certain areas. However, the study notes that increased humidity during heatwaves can partially counterbalance the cooling benefits, affecting human comfort levels. The economic and health benefits attributed to canals are substantial. According to the Canal and River Trust, the cooling effect of canals contributes to annual economic savings of £14.4 million, primarily through reduced losses in labor productivity during hot days. Additionally, canals promote active travel such as walking and cycling, which reduces carbon emissions and supports healthier lifestyles. These environmental and societal advantages align with broader efforts to integrate natural elements into urban planning to combat the effects of climate change. The study also emphasizes the role of canals in enhancing urban resilience against extreme heat. As climate change intensifies, the frequency and severity of heatwaves are expected to rise, making it crucial for cities to leverage all available resources for mitigation. While green spaces like parks and woodlands are commonly highlighted in climate adaptation plans, the research argues that canals should be similarly recognized as integral components of climate-responsive urban design. Their accessibility and proximity to densely populated areas make them valuable assets in promoting public health and community engagement. Experts warn that current urban infrastructure is ill-equipped to handle the projected increases in temperature. Approximately 92% of existing homes in the UK are at risk of overheating under a 2°C global warming scenario by 2050. The study calls for enhanced monitoring, social adjustments, and innovative urban designs to address these challenges. Incorporating canals into climate adaptation strategies could provide practical solutions, especially given their existing presence in urban landscapes and their capacity to support both ecological and human health. The findings have sparked interest among urban planners and policymakers, who are beginning to explore ways to enhance the visibility and accessibility of canals. Improvements in signage, connectivity with other green spaces, and better maintenance of canal pathways could further amplify their benefits. As the debate over climate resilience continues to evolve, the role of canals in mitigating urban heat islands offers a promising avenue for sustainable urban development.