การฟัง TOEFL

🎧 บทถอดเสียง

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 in cities, which means less shade and less cooling through evaporation. Third, human activities, like driving cars and running air conditioners, generate heat directly. Now, one interesting solution is to increase the reflectivity of surfaces, or albedo. For example, painting rooftops white can reflect more sunlight and reduce building temperatures. Another approach is to plant green roofs, which are covered with vegetation. These not only provide insulation but also absorb rainwater. While these methods are effective, they require initial investment. However, over time, they can lower energy costs and improve air quality. So, cities are increasingly adopting these strategies to combat the heat island effect.