If we are trying to get rid of carbon, why is it worse to put plastic in landfill than recycle it?


Wouldn’t it be better to bury as much of it deep underground as possible and seal it off?

edit – I should add that I do reuse and recycle, and I use as little plastic as I can afford to in the first place. I am just curious about this aspect

In: Earth Science

How does burying plastic remove carbon from the atmosphere?

Producing new plastic is not a process friendly to the environment. Recycling plastic reduces the demand for new plastic.

Reusing the materials is more eco-friendly than having to produce more of it. Recycling a ton of plastic means you don’t need to source the materials for creating new ton of plastic

Landfills basically aren’t “buried;” most of the time, the trash is basically left to decompose over time in relatively open air (or only lightly buried), meaning the CO2 still gets into the atmosphere.

Recycling keeps the carbon locked up in the plastic, which is (arguably) preferable to letting it be emitted into the atmosphere.

There are two different concepts going on. One is carbon sequestration, where we’re trying to take carbon dioxide out of the atmosphere and store it away to it doesn’t contribute to global warming/climate change. This is important to protect our current population/civilization from the side effects of climate change.

The other concept is sustainability/reuse; if we’re constantly draining our oil reserves to make new products and then burning/burying our old products, we will run out of oil to make new products. Reducing the amount of products used or finding ways to recycle/reuse them is important in trying to make sure that the resources we have can last for longer. This is a more long-term goal, so that we can continue living on the planet for longer, at least until we can colonize another planet. If we use most of the resources we have, there might be wars fought over the remaining resources, or we might run out and die off.

Those are separate issues.

We want Carbon out of the *air*. So, we should try not to burn as much stuff which releases Carbon Dioxide into the atmosphere.

Plastic is carbon, but it’s a solid. If we recycle it, it’s still a solid. None of this has anything to do with carbon dioxide levels in the atmosphere. Plastic is artificial and nature does not know how to break it down the way it knows how to break down natural carbon-based things (plants, animals, etc). So, if you put plastic in a landfill it will stay there for a very long time. Finding a way to process used plastic so that it can be re-used (or so that nature can break it down) is a good thing.

[It’s not, and your misgivings are correct.](https://criticalscience.medium.com/climate-action-sources-for-recycling-d0ab09e85a8a) Plastic is more expensive to recycle than to manufacture new, so our “recyclable” plastic waste is overwhelmingly sent to developing countries without the infrastructure to produce it themselves. Unfortunately, only a fraction of what goes in the recycling is recoverable, so the rest becomes garbage anyway – and these countries have much poorer waste management systems than the United States. Instead of a landfill, much of this plastic will get burned in rubbish heaps or dumped into the ocean.

Aluminum should absolutely be recycled. Other scrap metal is probably better off recycled as well. [**But if you live in a first-world country, it is usually more eco-friendly to send plastic to the landfill.**](https://old.reddit.com/r/slatestarcodex/comments/jxrjmv/recycling_much_more_than_you_needed_to_know/)

I believe that in areas where plastic is not currently viable to recycle, we should bury it, creating what in future could be considered an ore body of plastics. Imagine that in 50 years, we can easily and economically recycle plastics. Wouldn’t it be great to have a location with tons of this resource?

Carbon is in lots and lots of things. It’s in heavy solid things like rocks, plants, trees. It’s in lots of liquids like petroleum, bitumen and so forth. It’s also floating around in the atmosphere as CO2, methane, ethane and a variety of other gases.

Mostly the earth is fairly well adapted to having a certain amount of carbon floating around as CO2 and other gases. Climate change happens when we take the carbon that is in solid or liquid things, convert it into one of the gases and vent that gas into the air. Suddenly the earth has more carbon gas than it is used to and it gets upset.

The solution to climate change is to take a bunch of the excess carbon gases from the atmosphere and convert them back into solid or liquid things. This will happen naturally over time if we can stop creating new carbon gases, but we might be able to do this actively with technology. This is what we mean when we talk about reducing carbon.

In any case, plastics. Plastics are made by converting a solid or liquid that contains carbon into a different solid that contains carbon. So, even if you could magically eliminate all the CO2 that incidentally leaks into the atmosphere during plastic manufacture, you are still just taking a relatively climate safe form if carbon and converting it to a different, relatively climate safe form of carbon. You haven’t actually done anything to reduce the amount of carbon in the atmosphere. The best you can say is that you’ve kinda done nothing.

Except that you haven’t . Making new plastic causes A LOT of carbon gases to be incidentally produced. And most of these gases leak into the atmosphere. Then once you dump the plastic, it keeps on leaking carbon gases into the atmosphere. Recycling also leaks carbon gases into the atmosphere. It’s possible that it’s not even that much better than dumping the old and making new.


Plastics do precisely nothing to remove carbon from the atmosphere. However, making, recycling and dumping plastics all add carbon to the atmosphere. Therefore, if we care about climate change, we should remember that plastic use is never “climate safe” and let that fact shape our decisions about when and how to use it.


Before anyone says anything, most plastic alternatives (wood, metal, paper, glass) are in a similar situation regarding the climate. They all do very little or nothing to remove carbon from the atmosphere, and actually result in some amount of carbon being added to the atmosphere. The best you can do is to buy less, consume less and throw less away.

Landfills are not stable tombs forever because there is a lot of organic matter that naturally contains microorganisms, plus a fair amount of moisture in the buried materials.

Generally for the best packing, everything sent to a landfill is rolled over with a spike-wheeled roller machine that breaks up any bags and packaging to fill voids and level the landfill.

The entire mass becomes damp, the microorganisms start to grow, the pile becomes warm, and produce methane which some large landfills collect and burn off, or use to produce electricity.


Plastics recycling is difficult because it is very hard to sort the various types, and the fact that colored plastics can “spoil” other plastics that are clear.

Direct unsorted melting and forming usually ends up with an unsightly gray goo of all colors mixed together, and with unstable physical properties as a result of all the various types of plastic also being mixed together, plus also random organic matter such as paper or food waste also mixed in.


Generally the most effective form of plastic recycling is pyrolysis which applies high heat and pressure to mixed shredded plastics in a low-oxygen pressure cooker, causing the complex atomic polymer chains to break down into loose free atoms.

The heat and pressure is capable of breaking down toxic environmental poisons like dioxin which is a common ingredient in plastic production, and is not broken down when plastic is burned in an open fire in a backyard.

After the heat and pressure are reduced, atomic attraction forces reassert themselves, which then reforms the loose atoms into new and much simpler molecules of petroleum oil, gas, and carbon that is essentially purified coal that can be buried to sequester the carbon.

Recycling was created by the plastics industry as a temporary solution to the problem they created

If you were to bury a bag, you would just have to make another new bag, which takes energy and materials. Recycling old materials into new ones uses less energy and materials that have to be mined or drilled for than starting from scratch.