UO chemistry professor turns beliefs about environmental consumerism upside down

AX153_03BB_9.JPG Oregon Legislature debates banning plastic bags

David Tyler would like to dispel some myths about "green" consumerism.


, plastics expert and public speaker isn't really a crusader, though, so much as a numbers guy who likes to help people make sustainable choices based on facts rather than trends or clever marketing. Tyler is well-versed in the technique known as

a way of measuring a product's environmental impact throughout its entire existence -- from birth to death (or resurrection via recycling).

Tyler's talks can yield counter intuitive ways of thinking about everyday consumer choices. Here he sounds off about his way of looking at sustainability and previews his OMSI Science Pub talk tonight in Hillsboro.

What first started you on the path of studying sustainability?

The sustainability thing got started a number of years ago because I went across the street to the student union and they were giving, I think it was 50 cents off, if you brought your own ceramic mug instead of using one of their disposable cups.

I remember asking the guy, what's going on? He told me it's for environmental reasons. It's more sustainable to bring your cup.

I'd never heard of that before, and it turned out to be -- without giving out all of the data -- it turned out to be basically an urban legend.

So what's the fallacy there?

(A ceramic mug) has to be fired in a kiln at a high temperature for a certain period of time and you use a lot of energy to fire that ceramic mug. It turns out you might as well take the energy -- the natural gas or petroleum -- and convert it into plastic. No matter how much you reuse that ceramic mug, at least within the assumptions of a life cycle assessment, you never recover that energy you used in the manufacturing process.

But what if you're looking at it from the standpoint of litter?

Right, so that's the classic case of a plastic bag. A plastic bag is really good in terms of global warming impact, chemical use, water use, just all those environmental impacts we think about -- a plastic bag is really good compared to other types of bags.

But where it's really bad is it doesn't degrade, so it's easier for it to end up as litter. So if you see we have plastic bags blowing all around, or they're getting in our waterways and choking fish and that's the most important thing for you, then you ban them. But if you're more interested in global warming, you might come to a different conclusion.

So when you go to the grocery store do you get a plastic bag, a paper bag or do you use a cotton tote bag?

The most sustainable option is a reusable tote bag made out of recycled plastic.

That's interesting because the cloth bags are so vogue right now.

Well, cotton requires a huge amount of water to grow. So in terms of water use, cotton is really low on the list. It's bad for the environment in that sense. Also something like 25 percent of all pesticides used in this country are used on cotton.

David Tyler at OMSI Science Pub: "Paper, Plastic or Cotton Tote Bag? Life Cycle Assessments of Everyday Items"

When: 7 tonight

Where: Venetian Theatre, 253 E. Main St., Hillsboro

Cost: $5 suggested donation

So yeah, there are issues with cotton.

So another big choice for consumers right now is what kind of car you drive. The emphasis seems to be on gas mileage. Are there some other considerations people should be thinking about?

No. When they did the original life cycle assessment it showed that the Prius wasn't actually that good compared to a regular internal combustion engine car. But that life cycle assessment was redone with better data and better knowledge of how long the Prius is going to last. It turns out the Prius is actually quite good in terms of its environmental impact. So a Prius, or hybrid vehicles actually look pretty good.

What's another kind of product people might want to think about more before buying it?

Bio-plastics made from corn starch. They're not as green as we thought they were. It takes a lot of energy to grow the corn and make the starch. Conventional plastics look pretty good compared to a lot of those bio-plastics.

So what kinds of things will you be dealing with in your OMSI Science Pub talk?

So I don't want to give away my talk, but since this is a

and there will be people sitting around drinking beer, I've got a lot of life cycle assessment data on the manufacturing of beer. A lot of people think that's a fairly harmless activity but some of the data is absolutely amazing, the amount of greenhouse gas brewing beer produces.

I also talk about the impact of animals -- pets.

So you're coming up to the Portland area to challenge people on their beer and their dogs? It'll be pretty interesting to see how that turns out.

(Laughing) I don't come across as challenging them. I'm giving them something to think about.

-- Joe Hansen is a freelance writer