The Cool Trend in Global Warming

By Jelena Subotic

In all of the complexity of climate change, could an answer to one of the city’s problems really be black and white?

Yes, according to the folks at the White Roof Project, a NYC non-profit that’s “going green by painting white.” Founded in 2010, the organization recruits volunteers to paint NYC rooftops with a solar-reflective white coating, which reduces carbon emissions and cuts down on energy costs compared to the traditional black tar rooftop.

“Cool roofs,” as they’re called, along with solar reflective cars and cool color parking lots, are all types of reflective surfaces that help to reduce the effects of climate change. The basic premise behind this type of geoengineering is pretty simple. The darker a surface is, the more light it’s going to absorb. The lighter a surface is, the more light it’s going to deflect. So, the black tar roofs that are traditionally found throughout New York are actually trapping more heat and therefore requiring a lot more energy to keep these buildings cool during the sweltering NYC summers, hurting the environment and our wallets. Check out this EPA graphic from their Cool Roofs Compendium of Strategies to see this concept visual of this concept:

So can a rooftop paint job really make a difference? It can and it has, according to White Roof Project Board Member Heather B. James, “When we started this in 2010, we thought, ‘let’s just identify one building and coat the roof white,’ and we realized that it was an interesting, really easy, tangible change.”

After a whopping 100 volunteers signed up to coat that first 10,000 sq. ft. building, James and White Roof founder Juan Carlos realized that they were on to something good, “We were just floored, we thought wow this idea really has passion. It’s really popular. We need to keep this going.”

White Roof Project is one of the organizations that has participated in the NYC °CoolRoofs program, a collaboration between NYC Service and the NYC Department of Buildings that has helped to cool 5,768,347 square feet of NYC roofs.

NYC isn’t the only place participating in cool roofing, nor is it the first. According to the, U.S. Department of Energy, cool roofing has been around since the 1980s, but it wasn’t really until rolling blackouts in 2001 that researchers realized the value of cool roofing, “They found that cool roofing reduces peak demand for electricity, helping to lower costs and avoid power outages,” according to the DOE.

Although cool roofing is effective and growing in popularity around the world, it is particularly important in Urban Heat Islands like NYC. These heavily populated areas have a mass of dark surfaces, like rooftops and streets, and limited foliage, causing the area to be as much as 5-7 degrees warmer than surrounding rural and suburban areas, according to NASA.

If you’ve lived in the city for at least a year, you know not only how hot it gets in the summer, but also how cold it can get in the winter months. If the cool roofs keep heat from getting in, does that mean that it’s harder to heat up the buildings in the winter? Not quite, according to James, “There is a very slight heating penalty that comes along with having a white roof in the winter in the Northern Hemisphere but it’s negligible because it’s mostly indirect light that the buildings get from the sun,” adding, “in the winter the roofs are covered with snow, which prevents sunlight from hitting the roof either way.”

Unlike more expensive rooftop measures like solar panels or urban gardens, cool roofs are also dramatically cheaper to produce and maintain. Depending on the quality of the coating used, the price ranges from about 30 to 99 cents per square foot and for landlords offering low income housing, there is also a sponsorship program that takes care of some of the cost.

The coating lasts anywhere from 5-20 years and maintenance consists of spraying the roof down before the warmer months to get rid of the winter gunk.

A growing number of NYC buildings are cool roofing and the more, the better according to James, “When building share walls they share cooling impact. If you paint a 20 building row of white roofs, you’re going to maximize that benefit even more.”

Cheap, long lasting and effective, cool roofing proves to be another unique way that New Yorkers are successfully tackling climate change, this time one roof at a time.

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