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Plastic bags and plastic bottles – CO2 emissions during their lifetime

A number of people have asked about the implications of using plastic bags on the personal carbon footprint as well as on the environment in general. There are some comparisons between paper bags and plastic bags available which clearly show that it all depends on how many times these plastic or paper bags are being used.

Littering is probably the severest problem related to plastic bags. Nevertheless let’s now have a look at the carbon dioxide (CO2) emissions (carbon footprint) for the production and incineration of plastic bags.

Calculating the carbon footprint of plastic bags and bottles

The carbon footprint of plastic (LDPE or PET, poyethylene) is about 6 kg CO2 per kg of plastic. If you know the weight of your plastic bags, you can multiply it with the number of plastic bags you are using per year. Then you can easily calculate the carbon dioxide emitted by your own usage of plastic bags. See below for some background information.

  • The production of 1 kg of polyethylene (PET or LDPE), requires the equivalent of 2 kg of oil for energy and raw material (see here). Polyethylene PE ist the most commonly used plastic for plastic bags.
  • Burning 1 kg of oil creates about 3 kg of carbon dioxide (see e.g. our offline carbon footprint calculator). In other words: Per kg of plastic, about 6 kg carbon dioxide is created during production and incineration.
  • A plastic bag has a weight in the range of about 8 g to 60 g depending on size and thickness. For the further calculation, it now depends on which weight for a plastic bag you actually use. A common plastic carrying bag in our household had a weight between 25 g and 40 g. So I took the average of 32.5 g.
  • Take the above relation between kg plastics and kg of carbon dioxide, and you get about 200 g carbon dioxide for 32.5 g of plastic, which is the equivalent of the average plastic carrying bag in our household. Or in other words: For 5 plastic bags you get 1 kg of CO2.

CO2 emissions might be even higher

Of course you’ll find different figures on the Internet. The main factors are the weight of the plastic bag and whether the grey energy (energy used for production and disposal) is taken into account.

A new study from ETH Zurich in 2021 shows that CO2 emissions from plastic production have increased in recent years because plastic is increasingly produced in countries that use a lot of coal. The above values for CO2 emissions are therefore likely to be too low rather than too high.

CO2 Emissions of plastic bags
Plastic bags and plastic bottles - CO2 emissions during their lifetime 1

Juerg

ΞCarbon dioxide

31 thoughts on “Plastic bags and plastic bottles – CO2 emissions during their lifetime”

  1. Recycling of plastic and figures about plastic

    Some interesting facts around plastics:

    • The world-wide production of plastic is currently at 35 kilogramm per year per person. On average, it is increasing by 3% per year.
    • Most of the plastic is used for packaging (35%), followed by the construction sector and vehicle construction.
    • About 40% of the produced plastic is being disposed within 1 year (primarily packaging material).
    • The average lifetime of plastic is 12 years. The main reason is the relatively long lifetime in the construction sector.
    • Recycling of plastic saves on average about 2.5 kg CO2 per kg of plastic. Thus recycled plastic produces about 3.5 kg CO2 compared to 6 kg of CO2 for new plastic (production and incineration).
    • About 6% of the world-wide oil consumption is used for the production of plastic (with increasing tendency).

    Source: Pusch, Thema Umwelt, 1/2009, p. 3

  2. Plastics bags and CO2 Revised figures
    It is important to understand that the base for any calculation is verified. The risk is otherwise that final fugures will have a spread which is total unrealistic. In the production of typical plastic HDPE carrier bags you will get 100.000 bags from 1 MT of material, thus the weight is likely to be around 10 g/bag. Using your value of 6kg CO2/kg plastics 1 kg CO2 then will correspond to approx 16 carrier bags in HDPE. This is a very realistic figure. If you may recycle the bags and use that material at least in a 50/50 mix recycled material and virgin material the CO2 figure would of course be improved a lot as well. In Europe this is now getting more and more common in addition to that you have to pay a so called green fee for the bags in the shops. In Scandinavia and Finland this has been going on for a long time keeping the bag consumption on a very steady level. You could do the same in US providing that you organise your system for collection. Greetings from “The Nordic Light”

    1. Plastic bags CO2 emissions / content copy
      Ours is the original content. I have no problem if someone else is using our content, however a link back is considered as normal behaviour. Maybe they just forgot to do that without bad intention…

      Regards
      Juerg

      1. Tti Testing Labs / Polybag CO2 Emission Testing Program
        Dear Juerg,
        We want your report as we are helping the Local EPA in Pakistan to prepare a report on CO2 Emissions caused by burning Polypags in pakistan.

        Regards,
        Sarim Mehmood
        General Manager
        (Strategy & New Ventures)
        Tti Testing Labs
        http://www.ttilabs.net

      2. Co2 emissions
        what acids are putonto plastic that creates co2 emmissions directly from the plastic itself?

    2. It’s sad when people steal content
      To steal ideas from one person is plagarism. To steal from many is research. And even this I copied from some wise man!

    3. Plagiarisation.
      Apparently no longer….. Page not found. Although personally, think spreading the ‘green’ word should be rather considered a favour, not so much a crime.

  3. Plastic Bag vs Paper Bag
    Interesting to see a comparison of CO2 emissions between a plastic & paper bag production. My guess is that a paper bag production is far more carbon intensive – even using recycled paper.

  4. Source?
    Your statistics are very useful but where did you get this information from?

    1. Please read article about plastic and CO2
      Please read the original article on the top of this page about plastic bags and CO2 emissions and you will find it

      🙂

  5. Incineration vs. Landfill
    Isn’t it more useful to estimate the life cycle as production to landfill of a plastic bag vs. production to incineration? Or maybe I’m the only American reading this. 😉

  6. Plastics are byproducts!
    Just a reminder that plastic production comes from the feedstock of processing crude oil. Plastics come from the “waste” of producing gasoline. We need to use less gasoline to produce less plastic. For every bag that gets recycled, there are 5 brand new plastic bags being produced. REDUCE REDUCE REDUCE. Don’t forget your reusable bag. 🙂

  7. Transportation
    Very interesting, but what about the transportation of plastic bags from Malaysia and China.

  8. Mango Juice Manufacturers
    I absolutely adore reading your blog posts, the variety of writing is smashing.This blog as usual was educational, I have had to bookmark your site and subscribe to your feed in i feed. Your theme looks lovely.Thanks for sharing.

    Mango Juice Manufacturers

  9. conversion help
    could someone please convert for me the estimated atmospheric carbon from 48 million plastic bottles? This is average for bottles thrown out every day in the US.

    thanks
    Laura in central US

  10. So can I say that
    So can I say that non-biodegradable plastics emit CO2 as well? Just clarifying.

  11. 6 kg CO2 per kg of plastic
    Does this apply to PET empty plastic water bottles? And is the 6 kg of CO2 produced kg/cubic meters? Or kg/cubic feet?

  12. Lesson plans
    How can we cite this information for a teacher lesson plan?

    Thanks,

    Sandra

  13. GHG from plastic
    Of course, if you had mentioned the proportion of plastic to other products made this might have made sense.

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