Climate Change: The Five Types Of Green Roofs

Climate change has become one of the most major problems the world faces today. The World Bank Data in 2010 states that greenhouse gas emissions are increasing 6% faster than urban populations. Greenhouse gas emissions, or the greenhouse effect, is caused by the atmosphere absorbing heat from the sun. This helps the Earth stay warm, however, the generation of heat by burning fossil fuels is slowly destroying the planet, increasing the carbon dioxide or PPM (parts per million) in the air, which leads to air pollution. The World Health Organization states every year, an average of 3.3 million deaths have been counted due to air pollution. This type of pollution is quoted by WHO as the “world’s largest single environmental health risk.” (Tomazin

This is done to keep the same moisture level for all plants and give less weight to the roof. In an intensive roof, however, thicker soil is used to plant many different types of plants. This type of roof is considered as a “rooftop garden.” In an extensive roof, the bottom layer is a waterproofing layer, which covers the entire surface of the roof and prevents any leaks from entering the building. The insulation layer is resistant to moisture and temperature fluctuation (the irregular variation of rising and decreasing temperatures), and allows rainwater to pass to drainage systems. The drainage layer allows rainwater to flow from the vegetation layer, and collects excessive amounts of water and can prevent water runoff and sewer overflows. The geotextile layer separates the drainage layer from the plants, and prevents fine particles from clogging the drainage layer. Lastly, the vegetation layer is the surface for growing plants. ("Roof Garden Construction Guide | Step By Step" 2018) SOIL HERE. Vegetation removes air pollutants, since the plants use the carbon dioxide for photosynthesis, as mentioned. There are many types of plants that are used for green roofs, most commonly Sedum plants. These are succulent plants that have enough moisture to survive almost any climate. They are also a good lightweight solution for rooftops, having a mass of 35kg/m3. ("What Is A Green Roof? - Sempergreen" 2018) Green roofs provide stable temperatures at cool levels, whereas the temperature of traditional roofs can rise up to 32°C. They also provide protection for the roof membrane from harsh weather conditions, such as rainstorms. (Dowdey 2007) In plants, the pollutants are washed up by the rain, while the rest are absorbed by the plant’s tissues. Plants can reduce heat through the process of evapotranspiration, which is the natural process of cooling the