There's a lot of fuss about reducing plastic usage, and one of the main reasons seems to be that otherwise it will end up in the environment, particularly the ocean. But if I dispose of the plastic correctly so that it ultimately ends up in a landfill, how much harm does that cause?

I understand that some landfills are poorly managed and this can cause problems such as letting trash blow away. How hard is it to manage landfills properly? I haven't seen any campaigning for better landfills - wouldn't it be easier and more impactful to fix landfills than to convince every individual to reduce/eliminate plastic?

If the landfill does its job and buries plastic in the ground, how much harm does that do? The main problems mentioned on Wikipedia relate to biodegradable matter. From that perspective, for example, it seems I'm better off buying plastic bags to pick up dog faeces than biodegradable alternatives.

I thought the problem might be the costs of producing plastic, but for example this article claims that plastic bags generally use less resources and produce less carbon than other types of bag. I'm sure there are some kinds of products that shouldn't be produced using plastic, but anti-plastic campaigns don't tend to mention this kind of nuance.

  • You are right that a single plastic bag is more environmentally friendly compared to a cotton bag provided it's discarded properly (see also How many times do you need to use a cheap re-usable bag to offset its impact?), but the biggest problems with plastics in general are 1) environment pollution (plastic soup) and 2) since they are usually made from fossil fuels and often burned after usage, they contribute to global warming. Not using plastic solves these problems, but has other disadvantages.
    – THelper
    Commented Dec 25, 2018 at 8:59

3 Answers 3


The problem with burying plastic in landfills is that plastic takes ~500 years to decompose, and burying large amounts of waste leads to groundwater pollution in the surrounding areas, which is difficult to solve.

Reducing or eliminating plastic will help landfills in the long run because we cannot keep dumping our waste plastic in landfills, it will reach a saturation point.

While it might be true cotton totes mentioned in the article might produce more carbon while being transported and cotton is a water intensive crop, it can be reused and reduces the number of plastic bags going into landfills(assuming this is your concern), the conclusion in the article was to reuse any kind of bag for as long as possible.

Plastic pyrolysis is one solution being used by people to convert plastic into oil which can then be either further purified and converted to diesel or used as furnace oil. There is minimal pollution in this method as the gases(oil~60%, carbon black~10% and gas~30% are the 3 products) produced can be used to heat the reaction chamber.

  • Plastic pyrolysis sounds very interesting. Could you link to a webpage with more information?
    – THelper
    Commented Dec 25, 2018 at 7:46
  • "plastic takes ~500 years to decompose" but this alone is not a problem. What is the impact of plastic sitting around for a long time? "burying large amounts of waste leads to groundwater pollution" I alluded to this in my question - does plastic cause groundwater pollution (how?), or just organic waste?
    – Alex Hall
    Commented Dec 25, 2018 at 15:52
  • A bit of googling tells me that landfill space is starting to run low, which I wasn't expecting. That sounds like the most serious problem to me. Thanks.
    – Alex Hall
    Commented Dec 25, 2018 at 15:58
  • youtube.com/watch?v=gz0cwb0hEdg A simple video explaining plastic pyrolysis Commented Dec 26, 2018 at 15:20
  • waterencyclopedia.com/La-Mi/… link about groundwater contamination due to lanfills Commented Dec 26, 2018 at 15:21

In Ireland, plastics are exported for processing. There is a carbon footprint in the transport of these.

It's suspected that the purchasers of these are not always decent firms. Dumping of such shipments at sea may be responsible for some of the plastic islands in the sea.

When it does make it to India or China, it's often burned on the beach, causing pollution over there. So, with the best will in the world, not alone is the plastic you dumped burned, but there's a carbon footprint to bring it to where it was burned.

  • Take a look at this answer -- turns out the impact of trans-oceanic shipping is minimal compared to that of the waste itself. I think your point about not knowing how other countries are processing waste is strong -- even if they aren't burning it, how safe and efficient is the processing they are doing?
    – LShaver
    Commented Dec 26, 2018 at 16:50
  • -1 Your answer contains two claims without proof (the dumping and the burning) and from there generalizing as if this is the whole truth. In reality (e.g.) China has been a large importer of our plastic waste (until recently in 2018 when they seriously reduced that) and there is plenty of documentation showing that it is (was) recycled there.
    – user2451
    Commented Jan 30, 2019 at 7:38

There are three ways of handling plastic waste:

  1. Reuse. Unfortunately, plastic is hard to reuse (many different chemistries), but this may be a feasible approach in some very limited cases. Also, if you reuse plastic, there is a chance that the next user will choose to burn it, releasing carbon dioxide into the air, thus worsening climate change.
  2. Burn it. Unfortunately, this releases carbon dioxide to the air, thus worsening climate change.
  3. Bury it underground. It will then become a fossil fuel reserve in a million years or so. The carbon contained in the plastic won't be released into circulation, thus mitigating climate change.

The best option is obviously (3). Do make sure the plastic you use ends up in landfills! Even better would be a hypothetical world where all fossil fuel resources are used to make plastic and none are used for energy.

Now, some plastics are made from renewable sources. This doesn't matter! A carbon atom is a carbon atom. The atmosphere doesn't care if the carbon came from biological sources. Actually, by using wood to create plastic at a very large scale, and then subsequently burying the plastic underground, it is possible to achieve negative net emissions of carbon dioxide, thus not only mitigating but reversing climate change.

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