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 re-radiate heat. One effective mitigation strategy is increasing green spaces, such as parks and green roofs. A recent study in Melbourne found that adding trees along streets could reduce surface temperatures by up to 2.5 degrees Celsius during summer. However, the most significant cooling effect was observed in areas with a combination of shade trees and reflective building materials. The study also noted that while green roofs help with insulation, their impact on street-level temperature is limited unless implemented extensively.