TOEFLリスニング

🎧 リスニング原文

Listen to part of a lecture in an environmental science class. Today we're going to discuss the concept of 'urban heat islands.' An urban heat island occurs when a city is significantly warmer than the surrounding rural areas. This happens because buildings, roads, and other infrastructure absorb and re-emit the sun's heat more than natural landscapes do. For example, asphalt and concrete store heat during the day and release it slowly at night, preventing the city from cooling down. Vegetation, on the other hand, provides shade and releases moisture through a process called evapotranspiration, which cools the air. So, cities with more parks and trees tend to have lower temperatures than those with mostly pavement. A common solution is to increase green spaces and use reflective materials on rooftops, known as 'cool roofs.' However, implementing these changes can be costly, and city planners must balance environmental benefits with economic constraints. The effects of urban heat islands are not just about comfort; they can increase energy consumption for air conditioning and worsen air pollution. Therefore, addressing this issue is crucial for sustainable urban development.