Comment by xd1936
4 days ago
The argument that is pro-polyethylene plastic bags over cotton completely ignores the source: Renewable plants that are grown and harvested, vs. finite fossil fuels extracted from the Earth and refined.
> Instead of a simple blowing and sealing process, the cotton must be made into yarn, woven into fabric, prepared, dried, sized, dyed, and finished, which takes around 1,725 megajoules, around 3,050 times as much energy.
That conveniently ignores the drilling, extracting, transporting, refining, and transporting again to make "polyethylene resin".
> That conveniently ignores the drilling, extracting, transporting, refining, and transporting again to make "polyethylene resin".
It also ignores the energy requirements to grow the cotton. This isn't the gotcha you think it is.
The energy requirements for growing cotton being largely the sun, and a resource which makes up most of the universe (yes, I know water is several steps from hydrogen). ((And the tangentials like the fertilizers, dieslel etc.))
Compared to the energy requirements of petroleum based products: Incredible density and pressure acting on sufficient organic matter(thousands of times greater than growing cotton), on millenium time scales, then requiring several incredibly expensive and commoditization refining/distribution practices, and the end product is then ceremoniously burned off as poison or discarded into the aether.
It is 100 percent the "gotcha OP thought it is". However I do see/realize the fallacy you're pointing out in that the lesser of two evils is still evil.
I think the main point is that this post is not a good faith attempt to convince people otherwise. It's a shoddly researched opinion piece that has little to no merit as it ignores the complexities of producing either item.
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The energy to make the cotton bags presumably also involves lots of drilling and extracting, at least currently.
If we used oil only for plastics it would probably last us 1000 years. By that time we'd figure out how to grow plastics.
We can make plastic from synthetic oil. Synthetic oil can be made from plants or from carbon captured from the air.
Broadly, I agree with your comment. I have seen a few experimental plastic drink bottles that claim to have a minimum percent produced from plants. It is a little bit insane to imagine the amount of chemical and energy gymnastics required to make plastic bottles from plants, but, hey, the big drinks companies are desparate not to lose PET bottles. To be clear: I am not defending this type of plastic! I am only pointing out that it does exist.
This is really the key point! There are comparing apples to oranges.
Somewhat adjacent, in many rich countries, in the last 10 years there has been a big push to remove plastic drink straws. I think it might have worked. Initially, the designs and performance of wax coated paper straws were pretty terrible, but chemists and material scientists have been working hard to improve the product. I feel like paper-ish drink straws are here to stay.