Today in our environmental science lecture, we're discussing urban green spaces. A recent study in Melbourne found that adding more parks and trees in city centers can reduce local temperatures by up to 3 degrees Celsius during summer heatwaves. This cooling effect is mainly due to shade and evapotranspiration. Interestingly, the study also noted that while green roofs are effective for insulation, they have less impact on street-level temperature compared to street trees. The researchers recommend prioritizing tree planting along busy roads and near residential buildings, as these areas benefit most from reduced heat exposure. However, they warned that water availability is a key constraint in drier climates, so sustainable irrigation systems must be considered.