托福听力

🎧 听力原文

Listen to part of a lecture in an environmental science class. The professor is discussing the concept of urban heat islands. "Today we're going to talk about urban heat islands, which are areas in cities that are significantly warmer than their surrounding rural areas. This phenomenon occurs because materials like concrete and asphalt absorb and re-emit more solar energy than natural landscapes such as trees and grass. Additionally, human activities, including transportation and industrial processes, generate excess heat. The temperature difference can be as much as 10 degrees Fahrenheit on clear, calm nights. One interesting aspect is the role of vegetation. Trees provide shade and release moisture through a process called transpiration, which cools the air. So, cities with more green spaces tend to have less severe heat island effects. Urban planners are now using this knowledge to design cooler cities. For example, they might plant more trees on streets, create green roofs, or use reflective materials for pavements. These strategies not only reduce temperatures but also lower energy consumption for air conditioning and improve air quality."