雅思听力

🎧 Listening Transcript

Today in our environmental science lecture, we're discussing urban green spaces. Recent studies show that city parks not only improve air quality but also significantly reduce the heat island effect. For example, a park in Melbourne with over 500 mature trees lowered surrounding temperatures by up to 4 degrees Celsius during summer afternoons. However, the effectiveness depends on tree density and irrigation. Interestingly, the study found that even small community gardens with native shrubs can have a measurable cooling impact, though less than larger parks. The key is to integrate these spaces into city planning early, rather than retrofitting them later, as retrofitting costs are nearly double.