The only law that California’s politicians follow is the one involving unintended consequences.

Today’s example in progressive civil engineering comes from Los Angeles, where city officials have ordered streets to be painted white in an effort to combat climate change.

In the race to combat climate change, the city of Los Angeles is employing a surprising new tactic — covering its streets in a grayish-white coating known as CoolSeal. It’s sprayed onto the roadway with trucks, then spread across the surface with squeegees. However, its impact extends far beyond the edge of the pavement.

Los Angeles, like so many other modern cities, is encased in thousands of miles of asphalt. And dark-colored asphalt absorbs between 80 and 95 percent of the sun’s rays, heating up not just the streets themselves but the entire surrounding area. So when temperatures in Southern California rise above 100 degrees Fahrenheit, surface temperatures on its asphalt roads can climb to 150. It exacerbates a phenomenon known as the “urban heat island effect,” which the EPA says can add up to 22 degrees Fahrenheit to the average air temperature in a city, compared to the surrounding area.

The approach is based on the work of some researchers that ran some calculations in 2008 and came up with the conclusion that by having white roofs and streets, the Los Angeles area could reduce its heat footprint.

Last week, researchers at Lawrence Berkeley National Laboratory and UC Berkeley presented their study at California’s annual Climate Change Research Conference in Sacramento.

If the 100 largest cities in the world replaced their dark roofs with white shingles and their asphalt-based roads with concrete or other light-colored material, it could offset 44 metric gigatons (billion tons) of greenhouse gases, the study shows. That amounts to more greenhouse gas than the entire human population emits in one year, according to a recent article in the Los Angeles Times. The strategy could also offset the growth in carbon dioxide emissions, which account for about 75% of greenhouse gases, for the next 10 years.

… In 2009, the state will require that new and retrofitted residential and commercial, with both flat and sloped roofs, be installed with heat-reflective roofing. The requirements are part of California´s energy-efficient building code.

Globally, roofs account for about 25% of the surface of most cities, and pavement accounts for about 35%. Even without cutting industrial pollution from current levels, installing white roofs and pavements could offset more than 10 years of emissions growth, according to the conference data.

Since 2009, and the implementation of the white roof mandate, here is what the annual mean temperatures have looked like (see red circle).

The price for the white road topping is $40,000 per mile. Los Angeles has 6,500 miles of street; therefore, it will cost $260 million to coat all the streets in the quest to stop global warming.

Clearly, there seems to be little “bang for the buck”. In fact, a conducted by Arizona State University and entitled “Unintended Consequences“, is skeptical of the claims being made and assert that “a change in surface temperature has only limited effects on the overlying air layers such that overall benefits of reflective pavements and roofs can be less than expected.”

Another unintended consequence is something that Legal Insurrection fans in other locations may have experience with: White surface glare and its impact on the eyes.

Winter or summer, hours of bright sunlight can burn the surface of the eye, causing a temporary but painful condition known as photokeratitis. Over time, unprotected exposure can contribute to cataracts, as well as cancer of the eyelids and the skin around the eyes.

UV exposure also may increase the risk of macular degeneration, the leading cause of blindness in people over age 65. While cataracts can be removed surgically, there is no way to reverse damage to the macula, the area in the center of the retina.

Meanwhile, Los Angeles officials are still failing to address the exploding homeless population, which is the real health crisis. The unintended consequence of ignoring this human disaster may be another disease outbreak, such as Hepatitis A, that will be spread across the country.

On the upside, at least LA streets are not paved in shit, like those of another California city. At least, not yet.


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