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 urban heat island effect. For example, a park in Melbourne, Australia, was found to lower surrounding temperatures by up to 4 degrees Celsius during summer afternoons. Additionally, green roofs on buildings have become popular in cities like Toronto, where they help manage stormwater runoff. However, the lecturer emphasizes that the most effective design combines trees, shrubs, and grass, as this diversity supports more wildlife and enhances cooling. So, while small gardens are beneficial, larger interconnected parks yield greater ecological benefits.