Photo:abbyladybug, Creative Commons, Flickr
I’m compiling a list of bad environmental ideas. The first was sowing the ocean with tons of iron fertilizer to encourage phytoplankton, which only incidentally absorb the carbon dioxide (CO2) associated with global warming.
The second involves a Japanese invention I will simply refer to as "pseudo soil." This imitation soil is made from urethane (i.e., petroleum), so it’s lighter than regular dirt. In Japan, where buildings have strict load limits due to earthquakes, this pseudo soil will supposedly allow people to cultivate green roofs without having the roofs fall in from the weight of ordinary dirt.
Green roofs are becoming increasingly popular for good reason. Plants remove carbon dioxide from the air and are particularly beneficial in cities, where CO2 concentrations can be high. Green roofs also mitigate the “heat island” effect, which makes cities hotter than adjacent rural areas. This effect, though complex in nature, can be reduced to three basic elements: building density, impervious materials (including pavement), and a lack of plant matter. Plants lower temperatures by respiration; that is, they “breathe” moisture, which cools the surrounding air.
The problem with the aforementioned invention is the urethane itself. The EPA lists it as a hazardous air pollutant. When heated, it emits toxic fumes of nitrogen oxides. In plants, urethane inhibits ammonia oxidizing organisms normally found in soil. This oxidation is an important step in the nitrogen cycle (from atmospheric gas, to soil nutrient to plants). Urethane is known to suppress the germination of seeds by affecting the mitosis of plant cells. Urethane metabolizes to ethanol, then acetic acid (think vinegar). In the presence of urethane, ammonia converts to nitric acid, a toxic, corrosive substance. I’m not a chemist but I’m trying to imagine the full chemical “stew” created by urethane on a city roof in midsummer. I think massive amounts of CO2 might be an actual improvement.
Then there is urethane’s carcinogenic side. The International Agency for Research on Cancer has stated that urethane can be “reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity in experimental animals”. These experiments, which involved giving rodents urethane-laced water for three weeks, resulted in lung tumors. Other effects included malignant lymphomas, liver, spleen and uterine hepatomas, adrenal cortex adenomas, fibrosarcomas of the stomach and uterus, papillomas, melanotic skin tumors, pulmonary adenomatosis and adenomatous polyps. Urethane, otherwise known as ethyl carbamate, contributes to hyperplasia (excessive, random growth of cells), inhibits nucleic acid synthesis and depresses the immune system. Urethane is also associated with asthma, particularly childhood asthma, and has been linked to reproductive problems.
There is no need to add yet another chemical stew to our overburdened planet. Soil can be amended with peat moss to make it lighter. In the absence of peat, chopped straw (which is burned in the fields as a waste product of grain production) makes an excellent soil amendment, providing both lightness and nutrients. Shredded bamboo works equally well, and both straw and bamboo are renewable resources. In fact, sawdust – well composted with nitrogen-fixing amendments – makes an excellent soil additive, and is free for the taking from any lumber mill.
It’s time to look away from petroleum as a “useful” substance, and start seeing it for the toxin that it is. The idea of using it as soil is so dystopian – and so far removed from the natural processes of this planet – I have to wonder if the inventors are from another part of the solar system.
Please, no more bright ideas. There’s enough dirt laying around, and enough peat, straw and sawdust to lighten it, to green all the roofs in the known world. As my father used to say, "If it ain’t broke, don’t fix it."
Disclosure: I don't own stock in this future compay.
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Photo:416style, Creative Commons, Flickr