Today in our environmental science lecture, we're discussing urban green spaces. A recent study in Melbourne found that adding more parks and trees can reduce local temperatures by up to 4 degrees Celsius during heatwaves. However, the researchers noted that the benefit is only significant when the green area covers at least 30% of a neighborhood. In smaller patches, the cooling effect is minimal, and the cost of maintenance often outweighs the environmental gains. The study also highlighted that native plants require less water and attract more local wildlife, making them a better choice than exotic species for sustainable city planning.