[Edit: Take a look, Wired Online's "Observation Deck: Saving the Planet With Pavement" Has a new take on the issue, just released 06-15-12]
Global warming is a problem.
That being said, we obviously get heat from our sun.
Black absorbs light. White reflects light.
Consider that urban areas get roofing resurfacing regularly (20-30yrs) and paving rehauls even more frequently (~10yrs)
You see where this is going. Absolutely brilliant idea.
- Simply swap asphalt for concrete.
- Phase out black roofing. The new "cool roofs" don't need to be shiny. White is just fine.
Together, roads and roofs like this one cover about 60% of urban surface area,
a higher % than I would have guessed.
A hypothetical policy spanning latitudes 45°N-45°S would mitigate global warming extremely effectively. As AAAS explains:
"Achieving the same amount of cooling by slashing carbon dioxide emissions would require taking every automobile on the planet off the road for about 50 years."
This idea is not brand new by any means, however it's going to need a lot more attention in order for a big change to overcome the status quo. The New York Times mentions that comedian Jon Stewart even joked about it back in 2009. A similar policy already enacted, as InHabitat points out, enforces the people of Copenhagen to plant vegetation on their rooftops... Different... but by no means bad.
Emerging science is a great catalyst for change.
Precision data, some of the newest available, has allowed for better extrapolations from simulations. A study out of Lawrence Berkeley National Laboratory shows with significance several changes within the ecosystem of the Mojave Desert (the area of experimentation) Three sites were maintained: SOL, COOL, and CTRL. CTRL, as you'd guess, is the control. At SOL, photovoltaic surfaces (solar panels) were installed. The third site, COOL, simulated the cool roofing system that could have so much effect on us.
A reflectivity coefficient is referred to as a material's albedo. Studies of the effects of changed albedo in a given area have been done before, most heavily from 2008 on, but with some mixed results. It's hard to set up experiments that: A) have an effect on the area large enough to sift out signal from noise, and B) accurately measure the variety of meteorological data necessary for spread out simulations to be truly representative.
Interestingly enough, cool roofing has been seen to affect nearby rural areas in several ways. Summer afternoon temperature increases, and a correlation with less cloud cover AND lower precipitation emerges. These possible effects upon implementation of policy could make the situation a little bit hairier.
The idea's simple charm and ease of implementation is a recipe for attention and motivation. The idea still needs to spread far for international cooperation to come to fruition.
A department of energy building,
mandated by Dr. Steven Chu to have a white roof.
Tip of the hat to AAAS Science Now
Millstein, D., & Menon, S. (2011). Regional climate consequences of large-scale cool roof and photovoltaic array deployment Environmental Research Letters, 6 (3) DOI: 10.1088/1748-9326/6/3/034001
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