Today in our environmental science lecture, we'll discuss urban green spaces. A recent study in Melbourne found that parks can reduce surrounding temperatures by up to 4 degrees Celsius during heatwaves. However, the cooling effect is limited to about 100 meters from the park boundary. Interestingly, the size of the park matters less than the density of trees. For instance, a small park with dense canopy can be more effective than a large open lawn. The study also noted that water features, like ponds, add humidity, which can actually make the heat feel more intense. Therefore, the most efficient design combines shaded areas with dry, permeable surfaces.