雅思听力

🎧 Listening Transcript

Today, in our environmental science lecture, we'll discuss urban heat islands. These are areas in cities that are significantly warmer than surrounding rural regions. The main cause is the replacement of natural land cover with materials like concrete and asphalt, which absorb and re-emit heat. Additionally, waste heat from vehicles and air conditioning units contributes. One surprising fact is that even city parks can be warmer than expected if they have large paved areas. To mitigate this, cities often plant trees, which provide shade and cool the air through evapotranspiration. However, the effectiveness depends on tree species and placement. For example, trees planted along streets are more beneficial than those in isolated clusters.