Roof gardens are more popular in urban environments especially in the last ten years. They are frequently used as, social, symbolic, and contemporary space. Roof planting provides food, temperature control, hydrological benefits, architectural enhancement, a habitat for wildlife, and recreational opportunities.
Studies have shown in the past that plants have the ability to reduce the overall heat absorption of the building which then reduces energy consumption. Another great benefit is to reduce the overall heat buildup in cities like Los Angeles, the absorption of solar radiation by roads and by buildings. Plants however do not raise more than 5 F degrees above the ambient and are sometimes cooler. This in fact cools the environment up to 20 F degrees less. Roof garden cooling abilities become more necessary in warmer areas.
Other benefits are reduction of carbon dioxide impact, reduction summer air conditioning cost, and reduction winter heat demand lengthen, and remove nitrogen pollution in rain fall naturalizing acid rain and finally provides songbird habitat. This is according to the study in the University of Cardiff.