Today in our environmental science lecture, we'll discuss urban green spaces. Recent studies show that parks and community gardens can reduce city temperatures by up to 5 degrees Celsius during heatwaves. However, the key factor is not just the number of trees, but their distribution. Researchers found that neighborhoods with evenly spaced small green areas experience greater cooling effects than those with one large central park. This is because shade and evapotranspiration are more effective when spread throughout the city. Additionally, green roofs on buildings contribute significantly, but they require regular maintenance and are less effective in older structures.