Today in our environmental science lecture, we'll discuss urban heat islands. Cities tend to be warmer than surrounding rural areas because concrete and asphalt absorb and re-emit heat. One effective mitigation strategy is increasing green spaces, such as parks and green roofs. These areas provide shade and release moisture through evapotranspiration. However, the placement of these green spaces matters. For instance, a study in Chicago found that planting trees along residential streets reduced local temperatures by up to 2 degrees Celsius, but only when the trees were mature and densely spaced. In contrast, isolated trees had minimal impact. Therefore, city planners should focus on creating connected green corridors rather than scattered small parks.