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.' Professor: Urban areas tend to be warmer than surrounding rural areas, a phenomenon known as the urban heat island effect. This happens because buildings, roads, and other infrastructure absorb and re-emit the sun's heat more than natural landscapes do. For example, dark rooftops and asphalt parking lots can reach temperatures significantly higher than nearby grassy fields. Additionally, waste heat from vehicles and air conditioning units adds to the warmth. The lack of vegetation, which normally provides shade and releases moisture through transpiration, also contributes. Cities like Phoenix and Los Angeles experience this effect intensely. To mitigate it, some cities have introduced green roofs, which are covered with plants, and cool pavements that reflect more sunlight. These strategies can lower surface temperatures and reduce energy consumption for cooling. However, implementing them on a large scale requires significant investment and policy support. So, while the solutions exist, their adoption is not always straightforward.