托福听力

🎧 听力原文

Narrator: Listen to part of a lecture in an environmental science class. Professor: Today, let's talk about urban heat islands. This phenomenon occurs when cities are significantly warmer than surrounding rural areas. Why? Well, one major factor is the replacement of natural surfaces with materials like concrete and asphalt, which absorb and retain heat. Another contributor is the lack of vegetation, since trees and plants provide shade and release moisture through transpiration, cooling the air. But here's an interesting twist: not all urban areas experience the heat island effect equally. For example, parks and green roofs can create cooler pockets within a city. Also, the layout of buildings affects wind patterns, which can either disperse or trap heat. Some cities are now implementing 'cool roof' initiatives, painting rooftops white to reflect sunlight. This simple change can reduce a building's cooling costs by up to 20 percent. However, the effectiveness depends on the local climate and building design. So, while urban heat islands pose challenges, they also offer opportunities for innovative solutions.