Some environmental proposals aren't so green afterall

Reality can be so problematic.

Despite the noble intentions of going green, the effects often can be at odds with the goals.

Ethanol seemed like a good idea, until the studies showed that growing the corn and converting it to ethanol used more petroleum than just burning gasoline in the first place. It also has the added detriment of contributing to higher food prices.

What about corn-based plastics?

They seem like a good idea, but are they?

Not according to Tillman Grengross, a professor of bioengineering at Dartmouth College.

"The truth is corn-based polymers have, in my analysis, shown to be less energy efficient and less environmentally friendly than the fuel-based polymers," he said.

They seem like they should be good for the environment because you can compost them. Some of the plastic even smells like kettle corn. But, there also are real drawbacks.

Grengross said when a plastic cup, made from traditional petroleum-based plastic, is tossed into a landfill it's inert. The plasticizers, those chemicals added to mold the plastic and hold it in shape, become part of the cup, locked in for perpetuity.

Take the same style of cup in corn-based plastic and throw it in the compost pile. As it is decomposing, it gives off carbon dioxide and methane, which are both greenhouse gases. Then there is the matter of the plasticizers, which leach into the groundwater as the corn decomposes around it.

Grengross said, if, as a nation, we switched entirely to corn-based plastic, it would take 25 million acres of corn. Currently 3 percent of the fossil fuel we use now goes into plastic.

"It's perception up against reality," Grengross said.

Another example in food service is the case in which McDonald's discontinued using polystyrene boxes in the 1990s and moved to cardboard for its hamburger containers. Grengross said the company researched which was actually a greener product and found that the manufacturing process for cardboard actually uses more petroleum. In the manufacture of paper "they use more fossilized carbon than the entire material that ends up in plastic," he said.

Yet, the company also found that consumers thought cardboard was better for the environment, so that was why the company switched.

The 2006 mandate by Congress to increase the use of biofuels is another example of a little bit of knowledge being a dangerous thing.

"All of us who were in the field knew this was a train wreck on the way," said Steven C. Slater, the scientific program manager for the Great Lakes Bio-Energy Research Center at the University of Wisconsin.

"These issues are all very complex," he said. "What seems to be the obvious answer is not always correct; the correct answer is often counterintuitive."

For instance, he said, researchers are now looking at ways to use the stover, or the stalks and leaves, from the corn plants to make energy. The problem in that, he said, is that the combines that pick corn also grind up the stover, which is then dropped back onto the fields as fertilizer. If someone finds a use for that part of the corn, the energy to collect it, plus the need for additional fertilizer may outweigh the benefits of the new use.

Grengross has his own example of how recycling can be unproductive.

When people recycle plastic milk jugs, they wash them out with water, which has to be treated, pumped to their house, heated (because most people use hot water) and treated at a sewage treatment plant when it is poured down the drain. For each ton of recycled plastic, he said, consumers use about 10 tons of water to clean it.

On the other hand, he said, aluminum recycling makes a great deal of sense because it takes much less energy to reuse the aluminum rather than to produce more.

Despite the paradox, the positive aspect of the green movement, Slater said, is that if people try to live in a more environmentally friendly way they will notice the impact they have on the world.

"If it becomes stylish, it means people are starting to know about it," he said. "It becomes more of a cultural norm."

But, he said, the choices people make should be backed up by science, instead of marketing.

"You have to make sure your decisions are guided by reality and not what you hope reality would be."

E-mail Ann Belser at abelser(at)post-gazette.com

(Distributed by Scripps Howard News Service, www.scrippsnews.com.)