TOEFLリスニング

🎧 リスニング原文

Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about a fascinating phenomenon called 'urban heat islands.' Now, cities tend to be warmer than surrounding rural areas, sometimes by as much as 5 to 10 degrees Celsius. Why? Well, several factors contribute. First, concrete and asphalt absorb and retain heat during the day and release it slowly at night, preventing the city from cooling down. Second, buildings block wind and create canyon-like effects that trap heat. Third, human activities—like driving cars, running air conditioners, and using electricity—generate waste heat. Now, you might think trees could help, and indeed they do, by providing shade and releasing moisture through transpiration. However, many cities have removed trees to make room for development. Some cities are now implementing 'green roof' programs, where they plant vegetation on rooftops. These roofs not only reduce heat absorption but also improve insulation, cutting energy costs. So, while the problem is serious, there are practical solutions emerging.