- Green roofs allow for a building to use 10% less energy during winter months
- While typical roofs can have a daily temperature fluctuation of 45oC, green roof temperature fluctuations are just 6oC
- A city that uses green roofs can reduce city-wide temperatures by up to 5oF
- It takes just 6 years for the cost of a green roof installation to be recouped through savings and benefits
Photo by CHUTTERSNAP on Unsplash
Current Problem
As more of the world continues to urbanize and cities grow, green space is often being replaced by skyscrapers, roads, and other man-made structures. This rapid growth in urban environments in recent decades has led to some unexpected issues.
The standard way to build new structures has focused primarily on cost and reliability of materials, and what went on the rooftop was never a top concern. Unfortunately, that concrete or steel rooftop has led to the unexpected result of urban heat islands. Collectively, these buildings reflect and amplify the heat from the sun, raising the temperatures in cities to dangerous levels beyond what is healthy, a problem only getting worse amid climate change.
Another growing problem with our city landscapes is dealing with stormwater. While natural environments thrive on rain water and can absorb, use, and direct it properly, the concrete jungles that are cities have to build a specific sewer systems to handle heavy rains. Even still, these systems can often fail, which is another issue as extreme weather caused by climate change becomes more common, and run to issues like flooding, water system pollution and contamination, adverse health impacts from standing water, and more.
A key solution to overcome the above challenges of an urbanizing environment comes via reevaluating what these buildings can, and should, look like. Typically rooftops in cities go unused, but a trend in recent years has been to convert urban rooftops into green roofs.
A green roof is defined as a rooftop that has waterproofing membranes along with installations of vegetation and plant life.
Through green roofs plants can perform their natural ‘lung’ function for air quality, they can retain the heat in their soil that would otherwise be expelled and create more drastic hot days, and even reduce the heating and cooling needs of the building underneath them.
Modern green rooftops are not only functional, but also aesthetically pleasing and act as a bit of a green oasis for those who may get overwhelmed by the concrete jungle. From locality to locality, new techniques and implementations are coming along that are worthy of attention.
Emerging Solutions
Los Angeles
The city of Los Angeles is perfectly primed for green rooftops that will appeal to environmentally conscious communities while providing a getaway from the sprawling urban environment and rat race of driving from place to place. There’s no single ‘type’ of building best suited for green rooftops, Los Angeles citizens have shown that to be the case by ensuring green rooftops show up:
- In residential buildings such as those in Sherman Oaks
- On public buildings such as the Los Angeles Museum of the Holocaust
- To grow herbs on the rooftop of the very restaurant those herbs are utilized
- On commercial buildings across the city
California
Cool California has taken the initiative to make living roofs available across the Golden State. This non-profit identifies the benefits to building owners and occupants by assisting them with green roofs designs and implementation. Green roofs also enhance the ecosystem for California’s native plants and pollinators – to bolster local environments, while combatting climate change with more green space and reduced energy costs.
National
The National Parks Service (NPS) has looked into green roofs quite extensively in their mission to help reduce environmental and climate impacts of development, best manage storm water in urban environments, and ensure that the urbanization across the country won’t lead to unnecessary ills. Specifically, the NPS has put out a great set of resources detailing the benefits of green roofs (economic, environmental, urban planning, climate, and more). While no comprehensive national guidelines or standards exist for green rooftops, the NPS resources offer a set of beneficial case studies including:
Global
Egypt has sought to gain the air quality, shading, cooling, and other benefits of lush green spaces via green roofs. Green roofs are a key component of Egypt’s future climate strategy. As noted in a report from the United Nations Framework Convention on Climate Change, green rooftops were highlighted as a key solution in Cairo, the nation’s largest city, to help offset growing issues associated with their population growth: environmental degradation, heat islands, storm water management, lack of biodiversity, air quality problems, struggling to keep up with power demand, and more.
