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. This is known as the urban heat island effect. Why does this happen? Well, several factors contribute. First, buildings and roads made of materials like concrete and asphalt absorb and store more solar energy during the day than natural surfaces like soil and vegetation. At night, they release this heat slowly, keeping cities warmer. Second, cities have less vegetation, which means less shade and less cooling through evapotranspiration. Trees and plants release water vapor, which cools the air. Without them, temperatures rise. Third, human activities generate heat—from cars, factories, and air conditioners. So, cities can be several degrees warmer than nearby rural areas. This effect has significant implications for energy consumption, as people use more air conditioning in hotter urban environments. It also affects air quality and public health. Some solutions include planting more trees, using reflective roofing materials, and creating green spaces. However, these solutions require careful planning and community involvement.'