Nghe TOEFL

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Listen to part of a lecture in an environmental science class. The professor is discussing the concept of urban heat islands. Professor: Today I want to talk about urban heat islands, a phenomenon where cities are significantly warmer than surrounding rural areas. This happens because materials like concrete and asphalt absorb and re-emit heat from the sun more than natural landscapes do. Additionally, waste heat from vehicles and buildings adds to the effect. But there are strategies to mitigate this. One approach is increasing vegetation, such as planting trees and creating green roofs. These not only provide shade but also release moisture through evapotranspiration, which cools the air. Another strategy is using reflective materials for rooftops and pavements, which reduce heat absorption. Interestingly, studies show that even small changes, like painting roofs white, can lower city temperatures by a degree or two. However, these solutions require investment and planning. The challenge is implementing them equitably, especially in low-income neighborhoods that often lack green spaces.