Аудирование TOEFL

🎧 Транскрипт аудио

Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about urban heat islands. Now, as you know, cities tend to be warmer than surrounding rural areas. This is due to several factors, like dark surfaces absorbing heat, lack of vegetation, and waste heat from buildings and vehicles. But there's an interesting solution that's gaining attention: green roofs. Green roofs are covered with vegetation and soil. They help reduce heat in two main ways. First, plants provide shade, which lowers the surface temperature. Second, plants release moisture through transpiration, which cools the air. A study in Chicago found that green roofs can lower rooftop temperatures by up to 40 degrees Fahrenheit. However, there are challenges. Installing a green roof is expensive, and maintenance requires regular watering and weeding. Also, not all buildings can support the extra weight. Despite these issues, many cities are offering incentives to encourage green roof installation, because they also reduce stormwater runoff and improve air quality. So, while the upfront cost is high, the long-term benefits for both the environment and the building owner are significant.