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Monique Keiran: Conventional wisdom takes a blow

Back when I was young and fresh-faced, a University of Victoria researcher published a paper that shifted the ground under my idealistic, environmentally conscious, fair-trade sock-clad feet. The year was 1994.
Back when I was young and fresh-faced, a University of Victoria researcher published a paper that shifted the ground under my idealistic, environmentally conscious, fair-trade sock-clad feet.

The year was 1994. Scientists had published the first big studies documenting rapid, modern climate change. Alberta’s oilsands companies had publicly accepted government bailouts. Earth Day was big, and environmental education was the new cool, despite Canada’s conservative Fraser Institute’s statements that it constituted social brainwashing.

Chemist Martin Hocking’s paper presented an analysis of which type of beverage container was most energy-efficient to use — paper cups, ceramic mugs, glass mugs, Styrofoam cups or hard plastic cups. The answer surprised me and many others.

Conventional wisdom was that ceramic or glass — reusable — cups beat plastic or paper cups in eco-friendliness.

However, Hocking showed that you had to use a reusable cup, oh, about 500 times to equal the energy efficiency of a polystyrene foam cup used just once. He also showed that using paper cups once, then discarding them, used less fossil-fuel energy, per use, than any of the other cup types.

The problem with reusable cups was in washing them. Washing them took more energy than making them did. The energy to heat water to wash reusables also equalled or surpassed that required to make a Styrofoam cup, and was more than half that required to make a paper cup.

So, Hocking suggested, if you were going to use a reusable cup repeatedly for a long time, your environmental investment might — eventually — pay off. If, however, you broke or set the cup aside after a short time, paper or Styrofoam was a better choice.

Shock. Horror.

Some colleagues took this as permission to conduct their own long-term science experiments by not washing their coffee cups — ever. This also ensured everybody else kept their mitts and lips off those cups.

The analysis Hocking did is called a life-cycle assessment. Scientists have since scrutinized the life-cycle costs of an ever-increasing range of consumer goods and materials.

Hocking analyzed the energy consumed to make and use the cups. Today, researchers also examine biodegradability, water use, carbon dioxide emissions, toxic byproducts and other factors. Often, their results seem counterintuitive, too.

For example, it takes less energy and water and releases less carbon dioxide to make plastic grocery bags than it does to make paper bags. These analyses also indicate that plastic bags are a better choice than reusable bags made of cotton, which requires prodigious amounts of pesticides and water to grow. And, although plastic bags are made from petroleum, the amount used to make all the world’s plastic bags is so small compared to the amount used for transportation that eliminating plastic-bag manufacture would scarcely dent the world’s energy consumption or C02 emissions.

Plastic, however, leaches nasty chemicals. It also lasts forever, or breaks down into pieces that muck up the environment.

Glass and ceramic last forever, too. Ceramic cannot be recycled, and only small amounts of glass jars and bottles get recycled.

So, even with the information from life-cycle assessments, few definitive answers specify which product among a suite of similar products least harms the environment. The answers all depend on what you value most — Clean air? Clean drinking water? Litter-free landscapes?

As for reusable versus disposable cups, Ohio State University published a new assessment this year.

Their results suggest that new efficiencies make, for most U.S. regions, reusable cups a better choice than disposable Styrofoam cups when the cups are washed in a standard-sized dishwasher after one or more uses, and are used for many years.

In other words, more tempered recommendations. Life-cycle assessments merely provide guidance on consumer choices until more information becomes available.

And sometimes knock conventional wisdom on its ear.