托福听力

🎧 听力原文

Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about urban heat islands, a phenomenon where cities are significantly warmer than surrounding rural areas. One major cause is the replacement of natural surfaces with materials like concrete and asphalt, which absorb and retain heat during the day and release it slowly at night. Another factor is the lack of vegetation, which normally provides shade and cools the air through evapotranspiration. Additionally, waste heat from vehicles, air conditioners, and industrial processes contributes to the effect. The consequences are not just discomfort; higher temperatures increase energy demand for cooling, which leads to more greenhouse gas emissions. They also exacerbate health problems, especially during heat waves, and can worsen air pollution. To mitigate this, cities are adopting strategies like planting more trees, creating green roofs, and using reflective materials for pavements and buildings. These measures not only lower temperatures but also improve quality of life. Now, let's consider a specific example...