profiles, as a release of heat to the sky takes place throughout the night. The release of heat from the building occurs due to the absence of solar radiation, which reduces the sky temperature and enables the sky to act as a heat sink that promotes the transfer of heat from the building to the sky to achieve thermal equilibrium. A 2012 study by researchers at Concordia University included variables similar to those used in the Stanford study (e.g., cloud responses) and estimated that worldwide deployment of cool roofs and pavements in cities would generate a global cooling effect equivalent to offsetting up to 150 gigatonnes of carbon dioxide emissions – enough to take every car in the world off the road for 50 years. Types White cool roofs White thermoplastic membrane roofs (PVC and TPO), are inherently reflective, achieving some of the highest reflectance and emittance measurements of which roofing materials are capable. A roof made of white thermoplastic, for example, can reflect 80 percent or more of the sun's rays and emit at least 70% of the solar radiation that the roof absorbs. An asphalt roof only reflects between 6 and 26% of solar radiation. In addition to the white Thermoplastic PVC and TPO membranes used in many commercial cool roof applications, there is also research in the field of cool asphalt shingles. Asphalt shingles make up the majority of the North American residential roofing market, and consumer preferences for darker colors make creating solar-reflective shingles a particular challenge, causing asphalt shingles to have solar reflectances of only 4%-26%. When these roofs are designed to reflect increased amount of solar radiation, the urban heat island effect can be reduced through the reduced need for cooling costs in the summer. Though a more reflective roof can lead to higher heating costs in the colder months, studies have shown that the increased winter heating costs are still lower than the summer cooling cost savings. To satisfy the consumer demands for darker colors which still reflect significant amounts of sunlight, different materials, coating processes, and pigments are used. Since only 43% of light occurs in the visible light spectrum, reflectance can be improved without affecting color by increasing the reflectance of UV and IR light. High surface roughness can also contribute to the low solar reflectances of asphalt shingles, as these shingles are made of many small approximately spherical granules which