As a lighter material, concrete reflects more of the sun’s radiation than other building materials, helping reduce warming, particularly in urban areas.
To avoid excessive climate change, global temperature rise must be kept below 2°C. In addition to consolidated key strategies (e.g. energy, emission and materials production/design efficiency), geoengineering or climate engineering aims to alleviate the impact of climate changes.
The choice of highly-reflective surfaces, including concrete, falls within the class of geoengineering known as solar radiation management (SRM), which focuses on increasing the whiteness – and therefore reflectivity – of urban areas.
Albedo is the fraction of solar radiation reflected from a materials’ surface. Concrete has an albedo of 0.4, while asphalt has an albedo of just 0.1 (the higher the value, the higher the reflectivity). When used on vertical (buildings façades) and horizontal surfaces (roofs and pavements), concrete therefore has surface temperatures lower than darker solutions.
The use of concrete thereby helps to reduce the temperature increase experienced in urban heat islands (UHI), mitigating the impacts of climate warming. It can also help limit the use of cooling systems in buildings, as the external temperature around the building is lower due to the more moderate UHI, with the knock-on effect of reducing energy consumption.
Finally, reducing UHI lowers the risk of smog, as smog is more likely to form in higher temperature environments, with subsequent benefits to public health.
Header photo by Paul Moan on Unsplash