Nghe TOEFL

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Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about urban heat islands. As you know, cities tend to be warmer than surrounding rural areas. This is due to several factors. First, buildings and roads absorb and re-emit solar heat more than natural landscapes do. Second, there's less vegetation, which means less shade and less cooling through evapotranspiration. Third, human activities, like driving cars and running air conditioners, generate waste heat. The temperature difference can be significant, sometimes up to five degrees Celsius. This effect has consequences. It increases energy consumption for cooling, raises air pollution levels, and can even affect human health, especially during heat waves. However, there are mitigation strategies. Planting more trees and creating green roofs can help. Reflective materials on buildings can also reduce heat absorption. So, while the problem is serious, we have tools to address it.