雅思听力

🎧 Listening Transcript

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-emit heat. However, trees and green roofs can mitigate this effect. A recent study in Melbourne found that increasing tree canopy by 10% could reduce surface temperatures by up to 2.5 degrees Celsius during summer afternoons. The study also noted that the cooling effect was stronger in residential areas with low-rise buildings compared to dense city centers. Interestingly, the researchers emphasized that while green roofs help, they are less effective than street trees because they are often higher up and less accessible to pedestrians.