TOEFL Listening

🎧 Listening Transcript

Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about a fascinating phenomenon called 'urban heat islands.' This refers to the fact that cities are often significantly warmer than the surrounding rural areas. The main cause is the replacement of natural land cover with materials like asphalt and concrete, which absorb and retain heat. Additionally, waste heat from vehicles, air conditioners, and industrial processes adds to the effect. But here's an interesting twist: not all parts of a city heat up equally. Parks and green spaces can be several degrees cooler than nearby dense commercial districts. This is due to evapotranspiration from trees, which cools the air, and the shade they provide. So, urban planners are increasingly looking at green roofs and tree planting as strategies to mitigate the heat island effect. However, these solutions require careful consideration of local climate and water availability. For instance, in arid regions, planting water-hungry trees might be counterproductive. So, the key is to design sustainable urban landscapes.