Iki Maska (iki_maska) wrote,
Iki Maska

More dogma challenging

So there's a bunch of groups lobbying and legislating to ban shopping bags in the ACT to save us from global warming. From experience, full life-cycle cost can be fiendishly difficult to quantify. I look from time to time and the most recent calls prompted me to find this study:


Short version: Your re-usable shopping bag needs to last 100-ish trips to be more energy efficient than using disposable bags. That's about 2 years at one shopping trip a week. In our experience they last about 6 months.

So support packaging laws, but not blindly, and not to implement solutions that may make the situation worse.

BTW, we use long lasting calico bags that probably cost way more energy than the eco-bags.
  • Post a new comment


    default userpic
I'm suspicious of any study that is sponsored by a company that has something to gain from the result.

Isn't the big problem with plastic bags that they aren't at all bio-degradable, rather than the amount of energy that goes into producing them?
After doing some research, those polypyrene bags aren't bio-degradable either... not sure where you draw the balance for the environment between less landfill and less energy consumption.
If you use the reusable (or even a plastic bag) twice instead of getting a new bag each time then that reduces the landfill by 50%. It also reduces the potential for seal-strangling (or whatever the danger is) by 50%. Each subsequent use of the same bag reduces the amount going to landfill. Although there's a further factor to consider when bags are reused for purposes other than shopping, such as garbage disposal etc.

I'll have to read that report later when I have time. I'd like to know whether it includes the costs of running a landfill in its estimates of the cost of a plastic bag. I hope so! I doubt it's possible to consider all of the reuse options.
My feeling is that seal strangling and energy consumption should rate higher on the priorities than quantity of landfill generated. Thin film shopping bags aren't likely to be too bulky in landfill.

Your post also reminds me that free plastic bags tend to make sure people have rubbish bags with them when they buy food and tend to collect rubbish. You can observe this by looking at any bin in a picnic or camp site and seeing that lots of the rubbish tends to have been bagged in shopping bags. Would an absence of handy bags that came with your snacks and beer encourage more littering?
That's probably why they got RMIT to do the the study, their reputation is worth more than the money a "desktop" study like this would have cost. The most likely gain I can see is Woolies showing their customers they take their concerns seriously.

Yes, they get lodged in the gut of seabirds and turtles who then die a horrible lingering death. A lot of the bags used now are mostly plastic, but with starch links so they break down into small flecks of plastic that aren't (as much?) of an ingestion hazard. Ideally, the particles left should not float around in the water (http://en.wikipedia.org/wiki/Great_Pacific_Garbage_Patch). i.e. I'd rate low persistence as a more important attribute than energy consumed in manufacture.