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Which Is Greener? What You Said...

Is it really greener to buy milk in plastic jugs as opposed to glass or paper? The discussion on life cycle assessments of everyday choices will continue.

Is it really greener to buy milk in plastic jugs as opposed to glass or paper? The discussion on life cycle assessments of everyday choices will continue.

I’ve gotten a lot of responses to my post about life cycle assessments of everyday choices.

Plastic more sustainable than paper? Some readers didn’t buy it. They wanted to know who paid for the studies cited by University of Oregon chemistry professor David Tyler, what assumptions they’re based on and how they reached their conclusions. Great questions.

“I’m fine if this is correct,” wrote Kurt Kemmerer, “but I’m not likely to accept this blindly any more than I’ll accept the opposite blindly.”

“What a bunch of BS,” wrote reader kpd. “Since when does ‘environmental impact’ translate solely to ‘carbon footprint’?”

Others didn’t like the way the studies were framed. For example, why would you compare owning a dog to an SUV anyway?

“I think we should avoid making value comparisons between living creatures and wasteful material luxuries,” wrote Lorie Balie.

EcoGrrl said the conclusions drawn from the life cycle assessments are resulted in “a lot of overarching generalist statements that are extremely dangerous.”

“Plastic is not a good idea – ever,” she wrote. “Mankind created something that could never be truly destroyed or go back into the earth. Telling people to keep using plastic bags is just, well, twisted. Go see the inside of a bird’s stomach and tell me that styrofoam and plastic particles are better.”

There were some really thoughtful answers to the dilemmas these studies raise. Ronbikes4peace wrote that it’s less about the choice of material and more about the volume of material we use:

“When this whole concept was born in the 70s, reduce came first because it was understood that everything takes energy and we have to reduce the amount we use in order to sustain. Switching from one resource to another yet constantly looking to grow consumption will not get the desired results because it all takes energy. You have to reduce the amount being used. … None of it adds up if you continue to grow both population and consumption at the same time.”

Dave pointed out that the conclusion that ceramic mugs have more environmental impacts than disposable cups is misleading.

If you already have a ceramic mug, then its impacts per use will go down the more you use it, he wrote. He shared a link to a life cycle assessment that shows you can make up for the initial impacts of a reusable mug by using it many times over its lifetime until it reaches the “break-even point” where its energy impacts per use match those of a paper or plastic cup.

“Re-using something is always better than getting a new thing,” he writes, “and LCAs miss the intangibles that they can’t measure.”

Mike O’Brien noted that while he doesn’t completely agree with the conclusions drawn from the life cycle assessments, the discussion itself has value.

“Over the past 40 years of life in Portland we have become much more aware of the effects of our personal decisions, and this shift is the outcome of an ongoing community dialogue,” he wrote.

Let the dialogue continue! After thinking through Professor Tyler’s presentation, I’m starting to wonder whether there is more value in looking at life cycle assessments as a guide for shrinking environmental impacts overall – especially in the renewable materials that biodegrade – instead of using them for “do this, not that” instructions.

I think it will be worth taking a closer look at the assumptions made in the life cycle assessments Professor Tyler referenced in a future post. Thanks for your thoughts, and stay tuned…

Life-cycle analysis

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