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posted by martyb on Thursday January 19 2017, @05:06AM   Printer-friendly
from the tree-huggers-may-be-surprised dept.

AlterNet reports

It's a basic question faced by millions of shoppers every day: paper or plastic? Making the best choice for the environment, however, is less simple.

Last November, Californians approved Proposition 67, which upheld a 2014 ban on the issuing of single-use plastic bags in grocery and drug stores. As a result, shops were able to continue charging customers around a dime for reusable plastic or paper bags. The ban seems effective because it should lead to a reduction in plastic waste. More importantly, the extra charge aims to incentivize people to bring their own reusable bags to the store. But let's face it, many shoppers still forget, which brings us back to that darn choice we often have to make at the checkout line.

So, which option is better?

[...]The U.K. Environment Agency, a governmental research group, conducted a similar inquiry around the same time period. Its report[PDF] was a life cycle assessment comparing the environmental impacts of a variety of grocery bags. From extensive research, some of the study's key findings concluded that:

  • Single-use plastic bags outperformed all alternatives, even reusable ones, on environmental performance.
  • Plastic bags have a much lower global warming potential.
  • The environmental impact of all types of bag is dominated by the resource use and production stages. Transport, secondary packaging, and end-of-life management generally have minimal influence on their performance.
  • Whatever type of bag is used, the key to reducing the impacts is to reuse it as many times as possible.

The ecological break-even point with a cloth grocery bag comes on its 131st use.


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  • (Score: 1, Informative) by Anonymous Coward on Thursday January 19 2017, @06:48AM

    by Anonymous Coward on Thursday January 19 2017, @06:48AM (#455926)

    RTFA. The amount of resources that go into producing wood pulp from trees (water in particular) isn't insignificant.

    Paper bags are also much heavier, so transport is more resource-intensive.

    TFA takes on the usual assumptions head-on and shreds them.

    -- OriginalOwner_ [soylentnews.org]

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  • (Score: 4, Insightful) by choose another one on Thursday January 19 2017, @09:07AM

    by choose another one (515) Subscriber Badge on Thursday January 19 2017, @09:07AM (#455967)

    TFA was ignored though - it was some sort of inconvenient truth.

    The UK (where TFA was produced, and it was a few years ago) went ahead with a tax on "single-use" plastic bags anyway, to discourage their use - despite every other alternative being proven worse.

    What is politically best for the environment has nothing to do with what is actually best for the environment. That is why we are doomed.

    • (Score: 5, Informative) by TheRaven on Thursday January 19 2017, @05:41PM

      by TheRaven (270) on Thursday January 19 2017, @05:41PM (#456116) Journal

      From TFA, cotton bags need to be used 131 times to use less carbon dioxide than single-use bags (assuming that you use the single-use bags three times). We have a few that we've had for 4-5 years and seem to be in just as good condition as when we got them, in spite of being used most weekends for shopping, so I don't see a problem with that (they're also used in situations where we'd have needed to double or triple bag things because of the weight if using single-use bags).

      A few things that jump out from reading the study:

      • They assume cotton bags will end up in landfill or incinerated. Neither of these had occurred to us - when the bags wear out, we'd drop them in a clothing bank where they'd be shredded and used as cheap filler for blankets and similar.
      • The use of plastic bags as bin liners is important. Since plastic bags started costing 5p, we've been buying bin liners for small bins, which are cheaper - they are, however, also thinner.
      • The carbon dioxide numbers from the executive summary are interesting, but other forms of pollution were a more important factor in this ban. From Table 4, a cotton bag takes about double the energy and produces four times the waste of a plastic carrier bag. That means that if you use it five times, it's a better option than a single-use plastic bag. If you'd use the plastic bag three times (as they assume, then you'd need to use the cotton bag 13 times. That would represent an incredibly short lifetime for a cotton bag.
      • The maths for working out what proportion of bags end up being used as bin liners is quite suspect and contains a lot of hand waving.
      • The global warming impact for cotton bags in Figure 5.2 seems to indicate that they have a far lower impact than the statement in the executive summary.
      • The people who wrote this report have no idea how to do data visualisation.
      --
      sudo mod me up
      • (Score: 0) by Anonymous Coward on Thursday January 19 2017, @05:51PM

        by Anonymous Coward on Thursday January 19 2017, @05:51PM (#456124)

        > The maths for working out what proportion of bags end up being used as bin liners is quite suspect and contains a lot of hand waving.

        It's doubly questionable since ever since I don't have plastic bags anymore, I switched to other things like toilet paper or toast packaging as bin liners.
        For anyone willing to do that, they should not be counted as a useful use.

      • (Score: 2) by choose another one on Friday January 20 2017, @02:53PM

        by choose another one (515) Subscriber Badge on Friday January 20 2017, @02:53PM (#456548)

        While it is hard to work out what proportion of carrier bags are reused overall, you can know what _your_ reuse rate was. Ours was close to 100% - no bag was thrown away after first use _unless_ it broke so badly it became useless (only a very small percentage). Some bags we re-used more than once, so we're probably between 2 and 3 uses. Based on the table in the summary, cotton bags are 327 uses vs 100% re-used HDPE.

        We have had about 3 heavy duty cotton bags for several years (possibly >5, probably 10), they are used for supermarket shopping, maybe 3 times a week, usually taking one cotton bag with other heavy plastic bags inside, so that's 50 uses per year. Have they lasted 6 years - barely, they are falling apart have been patched/repaired several times and have really been in need of replacing for well over a year now. Also I suspect our bags (heavy cotton canvas with wooden handles) are actually a lot heavier than the cotton bags considered in the report.

        Are the cotton bags a better option? Not sure - it certainly isn't a slam-dunk.

        The impacts for bags in table 5.2 are assuming each bag is reused the suggested number of times, 5.1 shows the impact per-bag-produced, but not for cotton
        because it is too high (stated in the text). I guess they could have used log-scale for that, but that confuses people too...

        Comparing CO2 pollution is hard (as report shows) but it can at least be done. Comparing other pollution forms is impossible - how do you rate plastic vs cotton for destruction of the marine environment? Easy - plastic pollutes a lot, cotton not a lot. Except if you live near the Aral sea, in which case cotton causes total destruction of the marine environment. How do you account for that?

  • (Score: 0) by Anonymous Coward on Thursday January 19 2017, @04:51PM

    by Anonymous Coward on Thursday January 19 2017, @04:51PM (#456103)

    What is the problem in using water? The water is not destroyed. The higher demand for water leads to more research and development in this area. Sequestering carbon in wood-pulp reduces atmospheric carbon. Also every so called "estimate" for amount of resources that go into something I have ever read has been wild speculation that is at least 2 orders of magnitude off. I personally will always use paper over plastic, glass over plastic, and wood over plastic where ever I have the option to do so.

    • (Score: 0) by Anonymous Coward on Friday January 20 2017, @12:19AM

      by Anonymous Coward on Friday January 20 2017, @12:19AM (#456305)

      The issue is that we have a finite amount of fresh drinking water available at any given time. Getting more of it usually means having to pipe it in from far away and/or desalinizing ocean water. Both of which can be extremely expensive if you're in an area that doesn't have abundant fresh water available. Of that water, 20% is in Lake Baikal and unavailable to regions outside of Russia.