Nghe TOEFL

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Listen to part of a lecture in an environmental science class. The professor is discussing the concept of urban heat islands. "Now, urban areas tend to be warmer than surrounding rural areas, a phenomenon known as the urban heat island effect. This happens because concrete, asphalt, and buildings absorb and re-emit solar radiation more than natural landscapes do. Additionally, human activities like driving cars and running air conditioners generate waste heat. The temperature difference can be significant, sometimes up to 5 to 10 degrees Celsius at night. Why does this matter? Higher temperatures increase energy demand for cooling, which leads to more greenhouse gas emissions. They also worsen air pollution, as heat accelerates the formation of ground-level ozone. To mitigate this, cities have adopted strategies like planting trees, creating green roofs, and using reflective materials on pavements and rooftops. These measures not only cool the city but also reduce stormwater runoff. However, implementing them requires careful planning and funding. So, while the problem is clear, the solutions are not always easy to implement."