Today in our environmental science lecture, we're discussing urban green spaces. A recent study in Melbourne found that adding trees and parks to city centers can reduce local temperatures by up to 4 degrees Celsius during heatwaves. However, the researchers noted that the cooling effect is strongest within 50 meters of the green area, and it diminishes rapidly beyond that distance. They also observed that vertical gardens on building walls are less effective than ground-level parks for heat reduction, but they help improve air quality in narrow streets. The study recommends prioritizing small, distributed green pockets over a single large park to maximize benefits for residents.