The Untapped Potential of Rooftops in Mission 1.5°C
This post is a part of The Climate Tracker “Write for a Future Below 1.5 degrees” competition, which looks for young writers from around the world to share the necessity of staying below 1.5 degrees warming. The competition highlights natural and renewable energy solutions. 2 winners are selected to win a trip to Bonn, Germany for the May climate negotiations and to further develop their skills.
Rooftops are everywhere, but in the day-to-day, they do not warrant much thought. They are utilities to keep our heads covered and provide shelter, but are also blank canvases with enormous potential in addressing the global climate crisis.
1.5°C (2.7° F) is a precise number and discussed more often in the climate world than Oprah running for President in the Late Night TV realm. It is the number that Climatologists around the world have spent numerous hours, discussing years of research, to identify. It is the tipping point.
It may seem an obscure topic, but if global temperatures rise above 1.5°C on average from post-industrial levels, our climate will become unpredictable and create regions of inhabitability. All one needs to do is look at reports coming in regularly: extreme water crisis in Cape Town, devastating fires and floods, sea levels creeping up, and Swiss citizen’s desperate attempts to slow down glacial melting by covering them with reflective blankets.
According to a tweet from Yale360 Environment, a study in IOP Environment found that the difference of a global temperature rise of just .5°C from 1.5 to 2°C would result in an additional 5 million people being displaced due to sea level rise.
Don’t lose hope! We have numerous solutions at our fingertips to implement. This is where our rooftops come in.
3 Climate Conscious Rooftop Makeovers
I can’t help but notice while looking out my office window that of all the neighboring buildings, only one has solar installations, and only a few opted for a white “cool” roof. Our rooftops need to be transformed from desolate and barren zones into beacons of energy and life: multi-level buildings, malls, schools, and even our own homes.
Three climate-conscious makeovers for our roofs are solar, green, and white “cool.” Each is unique in composition and benefits: energy efficiency savings, carbon emission reductions and cleaner air, and each play a role in lowering Greenhouse Gas (GHG) emissions, improving energy efficiency, and reaching 100% renewable energy.
Go Solar
Rooftop solar is particularly important in our mission. Aside from the obvious benefit of increasing renewable energy consumption, it subsequently lowers GHG emissions and contributes to energy independence and sustainability. According to Google’s Project Sunroof, 29% (128K) of Philadelphia rooftops are solar viable. If the city’s full rooftop solar generation potential were realized, over 2.6 million megawatts of electricity would be produced from them per year. This is equivalent to emission reductions of removing 353K cars from the road per year or planting 42.8 million trees
The potential of solar rooftops has yet to be realized, and they are integral in reaching 100% renewable energy. The nearby Boroughs of Downingtown, West Chester, and Phoenixville have all made their commitment to 100% RE, so why not Philly? Just imagine all of that potential, and then scale it up to a state, national or international level.
Pick a Color
For rooftops which may be unsuitable for solar, there are two other transformations. Green spaces improve mental health and air quality, provide habitat for wildlife, increase resilience to drought and flooding, and filter greenhouse gases from our air. However, in our cities and suburban areas there are less opportunities for natural solutions to be implemented; thus, it is where green roofs can shine. Green roofs are literally a breath of fresh air in cities, and they can range from being minimalist with grasses and shrubs to oases.
According to the EPA, some of the benefits of green roofs are reducing the urban heat island effect, lowering air pollution levels and greenhouse gas emissions, and reducing stormwater runoff and flooding.
Green roofs are the ideal choice for temperate climates. Toronto is considered to be the green roof capital of North America with almost 700,000 square feet developed. However, in hot and arid regions, white “cool” roofs excel. This is due to the need for greater reflectivity.
A white rooftop is painted with a solar reflective coating that reflects up to 90% of sunlight. In comparison, conventional black rooftops only reflect up to 20%. While white roofs do not produce energy or remove carbon directly from the atmosphere, they improve energy efficiency and lower the urban heat island effect, indirectly reducing carbon emissions.
According to the Arizona State University Green Roof Energy Calculator the renovation of a Philadelphia “old” office building rooftop of 1500 sq. Feet to an 80% green roof would provide annual savings of roughly $137.06 compared to a conventional rooftop, and $11.21 more than a white roof. In Miami, a green roof would still result in $137.48 annual savings. However, a white roof would surpass it with around $175.66.
The idea of rooftop transformations is not novel. It has been circulating for over a decade – yet they are not being implemented at the necessary rate. When I look out my office window, I should see one of these three makeovers on every viable rooftop, not only 20%.
Climate-conscious rooftops are something we can implement today that will make a difference in how our climate story turns out 30 years from now – in whether we accomplish Mission 1.5° C. Any country, state or city – looking at you Philly – that is serious about tackling the climate crisis should be converting their rooftops.
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