Narrator: Listen to part of a lecture in an environmental science class.
Professor: Now, let's talk about urban heat islands. This phenomenon occurs when cities are significantly warmer than surrounding rural areas. Why? Well, one key factor is the replacement of natural surfaces with materials like concrete and asphalt, which absorb and re-radiate heat. Buildings and roads also block wind, reducing natural cooling. Additionally, human activities—such as driving cars, running air conditioners, and industrial processes—generate waste heat. Interestingly, the temperature difference can be as much as 10 degrees Fahrenheit on clear, calm nights. This has serious implications, including increased energy consumption for cooling, higher emissions of greenhouse gases, and even health risks during heat waves. One solution is to increase green spaces, like parks and green roofs, which provide shade and cool the air through evapotranspiration. Another is to use reflective materials on rooftops and pavements. Now, some cities have implemented these strategies, and studies show they can reduce peak summer temperatures by several degrees. But the challenge is retrofitting existing urban areas, which is costly and requires political will.
❓ 题目 What does the professor identify as a primary cause of urban heat islands?
A. A. The lack of wind in rural areas
B. B. The use of heat-absorbing materials in cities
C. C. The high population density in suburbs
D. D. The increase in solar radiation due to ozone depletion