Surface temperatures play a critical role in how hot the surrounding area gets and also present a health risk during extreme heat events.
During heatwaves, a substantial amount of the sun’s energy is absorbed and reflected by surfaces exposed to its rays, leading to their temperatures increasing significantly. These warm surfaces then transfer their heat to the surrounding air, increasing the overall air temperature. While some permeable and moist surfaces, like grass or soil, absorb less heat, other construction materials like asphalt or concrete are capable of absorbing as much as 95% of the sun’s energy, which is then radiated back into the surrounding atmosphere.
During days when the thermometer shows 38°C (100°F), this temperature refers to air temperature, which meteorologists usually measure over a metre (several feet) above the surface. However, at those temperatures, surfaces such as asphalt or cement can reach temperatures higher than 65°C (149°F), which can cause skin burns. It’s important to be aware of these surface temperatures and take precautions to avoid injuries.
URBAN HEAT ISLANDS
The process of urban development profoundly changes the landscape. Natural and permeable surfaces are replaced by impermeable structures like buildings and roads. This creates what climatologists call “urban heat islands”, areas within cities that experience significantly higher temperatures compared to nearby rural regions.
These are also areas with high concentrations of people. In Europe, nearly half of schools and hospitals in cities are located in urban heat islands, exposing vulnerable populations to health-threatening temperatures as climate change impacts worsen, according to the European Union’s environment agency.