Today in our environmental science lecture, we'll discuss urban heat islands. Cities tend to be warmer than surrounding rural areas because concrete and asphalt absorb and retain heat. However, planting more trees and creating green roofs can significantly reduce temperatures. A study in Melbourne showed that increasing tree coverage by 20% could lower daytime temperatures by up to 2 degrees Celsius. Interestingly, the effect is strongest during heatwaves, not on average days. This is crucial because heatwaves pose serious health risks, especially for elderly residents. So, while many focus on reducing carbon emissions, local cooling measures are equally important for public health.