 Is there anything more wonderful than a relaxing tropical island? Well, we're talking about a different kind of island, urban heat islands. Urban heat islands are areas and cities that have significantly higher temperatures than their surroundings. Heat islands form as the vegetation that provides shade and natural cooling is replaced by asphalt and concrete for roads and buildings. These materials absorb the sun's heat and releases it into the air, causing temperatures to rise. Waste heat from vehicles, factories, and air conditioners also add to the heat island effect. Using reflective roof materials and planting shade trees help reduce the heat.