การฟัง TOEFL

🎧 บทถอดเสียง

Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about urban heat islands, a phenomenon where cities are significantly warmer than surrounding rural areas. One major cause is the replacement of natural surfaces with materials like concrete and asphalt, which absorb and retain heat during the day and release it at night. Another factor is the lack of vegetation, which normally provides shade and cools the air through evapotranspiration. Additionally, waste heat from vehicles, air conditioners, and industrial processes adds to the effect. This temperature difference can be as much as 10 degrees Fahrenheit. But there are mitigation strategies. For example, green roofs, which are covered with plants, can reduce rooftop temperatures and improve insulation. Also, increasing tree cover and using reflective materials for pavements can help. However, these solutions often face barriers like high costs and maintenance concerns, especially in older cities where retrofitting is challenging. So, while we understand the causes, implementation remains a key issue.