Listen to part of a lecture in an environmental science class. Professor: Today we're going to discuss urban heat islands, a phenomenon where cities are significantly warmer than surrounding rural areas. This happens because concrete and asphalt absorb and re-emit heat more than natural surfaces like soil and vegetation. Also, waste heat from vehicles and buildings adds to the effect. But there are strategies to mitigate this. One is increasing green spaces, like parks and green roofs. These not only provide shade but also cool the air through evapotranspiration. Another approach is using reflective materials on roofs and pavements, which bounce sunlight back instead of absorbing it. Some cities have also implemented cool pavement programs, painting roads with lighter colors. However, these solutions can be costly and require maintenance. Interestingly, the heat island effect can also have a positive side in winter, reducing heating demands. But overall, the negatives, such as increased energy use in summer and higher pollution levels, tend to outweigh the benefits. So, what can urban planners do? They must balance cost, climate, and community needs.
❓ 题目 What does the professor imply about the solutions to urban heat islands?
A. They are universally effective regardless of local conditions.
B. They mainly focus on increasing building height.
C. They involve trade-offs between benefits and costs.
D. They are more beneficial in winter than in summer.
✅ 正确答案
They involve trade-offs between benefits and costs.