雅思听力

🎧 Listening Transcript

Today in our environmental science lecture, we'll discuss urban heat islands. Cities tend to be warmer than surrounding rural areas because concrete and asphalt absorb and re-emit heat. One effective solution is increasing vegetation, such as planting trees on streets and creating green roofs. However, a lesser-known factor is the albedo effect, where lighter-colored surfaces reflect more sunlight. A study in Los Angeles found that painting rooftops white could reduce city temperatures by up to 2 degrees Celsius, but this requires regular maintenance to remain effective. Additionally, shading from trees can lower energy use in buildings by up to 30 percent.