Australia’s cities are getting hotter, and efforts to reduce urban heat may unintentionally raise the risk of skin cancer, experts warn. As urban areas become increasingly sweltering due to climate change and the way cities are built, the use of reflective materials such as light-colored footpaths and roofs is on the rise. While these materials help cool the environment by reflecting heat back into the atmosphere, they also bounce ultraviolet (UV) radiation, a leading cause of skin cancer.
Researchers at RMIT University and SunSmart, a Victorian skin cancer prevention program, have highlighted that urban planning policies often overlook the impact of UV radiation. The unintended consequence could exacerbate Australia’s already alarming skin cancer rates unless addressed in city design.
The Growing Urban Heat Problem
Urban heat is a significant issue in Australia, where heatwaves are the deadliest natural disaster. High temperatures not only diminish quality of life but also pose a direct threat to public health. In response, city planners are using light-colored, reflective materials to mitigate heat by bouncing solar radiation away from the ground. These measures have been widely embraced, but new research suggests they may inadvertently increase exposure to harmful UV radiation.
Darker surfaces, such as bitumen roads, absorb solar radiation and become extremely hot during summer. In contrast, reflective materials such as glass, metal, and light-colored surfaces bounce both heat and UV rays back into the environment. Studies have shown that reflective surfaces can increase UV exposure by up to 300%, heightening the risk of skin conditions like melanoma, sunburn, and eye damage.
Australia, with the highest melanoma rates in the world, faces an urgent need to reconsider how urban planning can balance the goals of cooling cities and protecting public health. In 2019, over 15,600 new cases of melanoma were diagnosed, and this number continues to rise each year.
Gaps in Urban Planning Policy
The research team conducted a comprehensive audit of health-related policy documents across 79 local government areas in Victoria. They found that while sun protection was often mentioned in the context of reducing heat, UV exposure and skin cancer were rarely addressed.
In an analysis of seven planning policies, which collectively included 102 specific guidelines for improving outdoor urban spaces, only 21 addressed surface materials, with a focus primarily on reducing heat. For instance, many planning documents recommended the use of light-colored materials for paving and roofing, yet none acknowledged the potential increase in UV radiation from these materials.
A further workshop with 14 urban planners revealed significant gaps in training and support for decision-making around UV exposure. Key concerns raised included how to encourage outdoor activities without increasing UV exposure and identifying the populations most vulnerable to UV radiation.
Moving Forward: A Call for Better Planning
Experts argue that urban cooling strategies must be revisited to balance both temperature reduction and UV protection. Planners and designers should consider the placement of reflective materials carefully. For example, placing reflective materials on roofs or higher building facades could mitigate heat without increasing UV exposure at street level.
The integration of urban greenery, especially trees with large canopies, is another strategy gaining traction. Trees not only provide shade but also serve as natural barriers against UV radiation, making them a key element in urban cooling efforts. Experts recommend prioritizing the planting of more trees in cities to provide both heat relief and UV protection.
To address this issue, the researchers call for the development of evidence-based guidelines for local governments, ensuring urban planning decisions factor in UV protection. Further research into how urban design can best reduce UV exposure is also needed.
As climate change worsens, city planners will face increasing pressure to develop cooling solutions. It is critical that these measures not only focus on reducing heat but also consider the public health risks posed by UV radiation. By balancing both, Australian cities can stay cool while keeping residents safe from the dangers of skin cancer.
Related topics
