Today in our environmental science lecture, we'll discuss urban green spaces. A recent study in Melbourne found that parks can reduce local temperatures by up to 4 degrees Celsius during heatwaves. Interestingly, the effect is strongest when parks are larger than 2 hectares and include water features. However, the researchers noted that tree canopy coverage is more critical than grass areas for cooling. They also highlighted that well-designed green spaces can improve mental health, but only if they are accessible within a 10-minute walk from residents' homes.