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. 'Urban heat islands occur when cities are significantly warmer than surrounding rural areas. This happens because materials like concrete and asphalt absorb and re-emit heat more than natural landscapes do. Additionally, cities have less vegetation, which reduces shade and evapotranspiration—a process where plants release water vapor, cooling the air. Buildings also block wind, trapping heat. One major consequence is increased energy consumption for air conditioning, which leads to higher greenhouse gas emissions. Another issue is health risks during heatwaves, especially for vulnerable populations. To mitigate this, cities can implement green roofs, plant more trees, and use reflective materials on pavements. However, these solutions require investment and urban planning changes. Interestingly, researchers have found that even small parks can create cooler pockets, but their effect is localized. Therefore, a combination of strategies is needed to address the problem effectively.'