Today in our environmental science lecture, we'll discuss urban heat islands. As cities grow, concrete and asphalt replace natural surfaces, absorbing more sunlight and releasing heat at night. This makes cities warmer than surrounding rural areas. One surprising factor is the lack of vegetation. Trees provide shade and release moisture through transpiration, which cools the air. In a recent study of a mid-sized city, researchers found that adding green roofs to 20% of buildings could reduce peak summer temperatures by up to 2 degrees Celsius. However, the effect varies with building height and wind patterns. So, while green infrastructure helps, it's not a complete solution.
❓ 根据讲座内容，最近的研究发现增加绿色屋顶有何结果？
A. A. 它们对城市温度没有显著影响。
B. B. 如果应用于20%的建筑，它们可以将夏季峰值温度降低多达2摄氏度。
C. C. 它们仅对拥有高层建筑的城市有效。
D. D. 它们增加湿度，使城市感觉更温暖。
✅ 正确答案
B. They can reduce peak summer temperatures by up to 2 degrees Celsius if applied to 20% of buildings.