Which is better for ecology: paper or plastic shopping bags?
February 21st, 2010 | 
Author: I’m looking for a "reasoned" answer, based on understandable facts about how the use of each type of bag affects the planet.
I’m looking for a "reasoned" answer, based on understandable facts about how the use of each type of bag affects the planet.
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As with most non-trivial choices in life, the answer is "it depends". For instance, if you normally buy small trash can liners for your bathroom, then choose plastic grocery bags and quit buying the little trash can liners! That’s easy to see the benefit because YOU do the recycling. If your store takes-back the bags with a recycling program, then by doing that, you would not be adding too much to the demand for oil since those bags would be used instead of pumping more oil out of the ground.
If you’re just opposed to adding any demand at all to the oil markets, or are not convinced that your plastic bag recycling program will be effective, you can use paper. Although paper bags are biodegradable, they usually do not degrade much in a landfill. The problem with making kraft paper is that it creates dioxins, smells horrible, uses a ton of water, and, depending on the plant, might really pollute the river both chemically and thermally. You might find a few uses around the house for the kraft bags, or if you have a curbside recycling, the paper bags will recycle the same as corrugated cardboard. As with any recycling (plastic or paper), the process will use some new material (in this case, trees) and some old material (recycled paper). So even if you recycle paper or plastic, you’re still adding a little bit to the demand for trees and oil.
Of course the final option is to choose neither paper nor plastic, but that means lugging your own bags around. I’ve tried several, but I found myself not wanting to carry the bulky ones. The result was that all too often I ended-up getting plastic bags because I left the reusables at home. Recently I’ve found some bags that squish down so small you can always have them with you, yet still get a whole cartload of groceries in them (http://www.breezybags.com). So although I personally use reusable sacks now, I’d go with plastic if I could find a recycling program
I trusted.
The answer is somewhat convoluted.
Paper bags can biodegrade. They are also stronger, you need less of them to carry your groceries, so you use fewer bags. Paper bags are made from a renewable resource (trees) and can be carbon-neutral.
However, paper bags are very resource intensive (when compared to plastic). The amount of energy needed to grow, harvest and process wood to make a paper bag is significantly larger than what is required to make a plastic bag.
Plastic bags are lighter and thinner than paper bags, so you can ship more plastic bags to the store using less energy. As stated above, plastic bags use minimal resources to be made (they are a blown-plastic film), but are made from a non-renewable resource (petrochemicals – oil).
I believe the life-cycle analysis (a term used to describe this type of question) favors plastic bags. This is because they use less energy in production. However, it is quickly countered by the bag’s long-term impact on the environment.
All in all, the general consensus is that a reusable bag (like a canvas bag) is ultimately the best for the environment. While being rather resource intensive to produce, a reusable bag has the advantage of being reusable. After a number of uses, the production costs (energy, transportation, etc) of a reusable bag are off set by not using an ever increasing amount of disposable bags. Most grocery stores will offer a $0.05 discount for every reusable bag you use (helping you pay for the reusable bag).
Neither bag is overly good for the ecology. The reasons are different for the statement but the general idea is that they are both just as bad.
1st Paper Bags require the destruction of forests to produce the paper. Much of these forests are now SFC certified but that does not preclude the fact that trees are being cut down to make the paper. The other issue with paper bags is the amount of water and chemicals used in the manufacture of the bags. Brown Bags are less detrimental in that they use less bleach in the processing but they still use clorine and other chemicals to treat the fibers so that the bag can be made as strong as possible.
Plastic Bags on the other hand are a petrolium product. Oil is the key ingredient and as a result of the use of plastic bags the need for oil is no less in demand. Aside from the oil demand placed by Plastic bags there are other issues that one needs to address that result from the bags. plastic does not biodegrade it photodegrades and as a result never fully goes away. Pieces of plastic travel the world and eventualy ends up in water ways, oceans, and in the things we eat. Fish are most commonly affected by the plastic but often times so are birds and other mammals. Plastic bags are unsightly and destroy the pristine view in nature they leach chemical compounds into the soil and then into the water supply or the food chain.
Both Paper and Plastic can be recycled which is a plus and no matter what the choice is if the person who makes the choice between the two doesn’t also choose to recycle then neither one is a good choice.
Personaly when possible I opt not to have a bag. and when I carry large amounts of groceries I bring my own cloth bags made from renewable natural fibers like hemp, organic cotton or bamboo. That truely is the best option.
There are a lot of variables, was the bag made from recycled matter, is it going straight to the landfill, will it be used again, plastic takes longer to breakdown but with most stores recycling is recycled more often. Mine would only be a guess but I would say they are close to even. So why not go with the easy and obvious answer of using neither. Stash some canvas bags in the car and when you go tell them they can keep them both. Many stores now pay a nickel or dime per bag you bring in and I have yet to have one of my canvas bags rip or get a hole in it as the others do.
Here’s a couple points:
Paper bags do biodegrade and rather quickly and as the first poster has said more can be put in the paper bags so the energy and cost ratios equal out. I also reuse the paper bags I get many times before recycling which is also easier than the plastic (we only need so many plastic park benches).
Also, while trees are cut down for making the bags, those trees are also grown for making those bags and I’d rather have a tree farm (though better if it’s diverse which they aren’t always) than a plastic bag factory on the land which is often the alternative. If the land isn’t being used for trees then it will probably be used for something else less savory.
Plastic can be recycled but it just isn’t. Out of something like 600 BILLION plastic bags given out in the US, only 1 or 2 percent are recycled. The rest end up in landfills where they never breakdown (nor does the stuff inside them) even if they are the "biodegradable" kind (since it needs sunlight or high temps to break up) or rather than even make to the dump they are floating around the earth and oceans (both places that paper would decompose back into the environment).
http://farm3.static.flickr.com/2302/2258997139_2230b7cc4e_m.jpg
What plastic that does degrade only breaks into smaller pieces which then get into the food chain as animals mistake it for food (sea life thinks it’s plankton for instance) and often end up starving to death from malnutrition and blockages. Also the chemicals released are very harmful and those can transfer to humans who eat the seafood as the chemicals are cumulative and persistent (PCBs, Dioxins, BPA, perchlorate, etc) and become more concentrated going up the chain (tuna for instance as a predator themselves have a lot of mercury from the fish they’ve eaten):
http://www.287reasons.com/yourbodyburden.html
There’s a massive "plastic island" in the Pacific of swirling, floating, discarded plastic crap that is twice the size of the United States and growing. This is not just killing fish and other sea life it is outnumbering them 6 pounds to 1.
http://www.independent.co.uk/environment/the-worlds-rubbish-dump-a-garbage-tip-that-stretches-from-hawaii-to-japan-778016.html
http://www.onebagatatime.com/
Some pics for your viewing displeasure:
http://farm1.static.flickr.com/36/97923478_b867519206.jpg
http://svmomblog.typepad.com/photos/uncategorized/2007/10/19/garbage.jpg
http://www.helixcharter.net/department_sites/socialscience/honors_geo/student%20work/Period%203%20websites/t3moldewatpol/images/plastic%20ocean%20trash.jpg
http://www.mindfully.org/Plastic/Ocean/Moore-Trashed-PacificNov03.htm
"Strange Days" from National Geographic shows how our actions can be like the wings flapping on a Butterfly around the world:
http://www.pbs.org/strangedays/
http://www.msnbc.msn.com/id/24257539/
http://en.wikipedia.org/wiki/Butterfly_effect
Ed Norton who hosts the shows says:
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“People say, ‘What’s the one thing they could do to help?’ I say you gotta do more than one thing,” he said. But, he continued, “One thing for sure is the bags. Plastic bags are turning out to be one of the worst stupidest things that we’re doing to the environment. Those little bodega-deli plastic bags we use for 30 seconds and then throw away.”
He wants them banned, a move many countries have already taken. “When China is ahead of us in banning these things, when other countries around the world are banning these things, we need to get in line with that and catch up,” he said. “That is a simple, small thing that everybody can do—forget about those silly plastic bags.
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So my advice is don’t stop just at bags when avoiding plastic.
The paper industry has been very succesful at getting Americans to believe paper is more envronmentally friendly. This is not true:
A typical heavy plastic bag uses 60% fewer resoruces to produce than a regular paper bag. In spite of the plastic being made from petrochemicals, it requires far less energy to produce the plastics used, than are required to produce paper. Additionally, it requires less energy to recycle plastic than paper.
There are a lot of myths about plastic. One is that lots of oil is required to produce them. In reality, the feed stocks often come natural gas. Further, all of the plastics used in north America, in 1 year, consume the equivalant of about 1 days worth of total annual oil consumption.
If you think about what is required to produce paper, the answer becomes even more clear:
1. Cut road into forest
2. Cut down trees
3. Transport trees to mill
4. Covert wood into pulp by heating, and chemical treatment (this step alone uses more energy than is required to polymerize the polyethylene used in plastic bags)
5. Spread the pulp
6. Dry into paper
Recycled paper requires less enegy in step 4, but 100% recycled paper does not have the strength required for packaging, which is why it is often bleached (another chemical process) and used for copier and printer paper
On the other hand plastic can just be ground up and remelted, at temperatures around 350 deg F.
There is an economic reason plastic has become so prevelant. It is less expensive to produce, because it requires fewer resources and less energy.
Finally. If you throw plastic away it takes up only about 20% of the space of paper.
In the oxygen free envronment of a land fill, paper does not biodegrade. If you compost your paper, it may have an advantage in this regard. If you just throw it away or recycle, not!
By the way. Reusuable bags are great. However, it takes about 200 uses to make up for the additional materials used to make them. If you use cotton, as opposed to polyester reusable, that number doubles.
Note: This is the same answer as given to the same question 1 week ago.
One more point. Plastic is a means to capture carbon and is therefore positive from that standpoint as well
I know this won’t help much, but in general, either can be good if you reuse them. I see that others have given great responses, so this is just an added note. If you really want to help the planet, reuse either type of bag.
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I think it matters less how much energy it takes to produce the bags or what material they are made from. The design of the plastic bag guarantees that many will become litter. They are light weight and become parachute like with the slightest breeze. Millions of them blow away when they are emptied outside, blow out of garbage cans, trucks, recycle bins and landfills. They can become air born and fly great distances, they are found in most ecosystems and are fatal to many animals both land and sea. They can never become a good thing for the planet, when they are large animals become entangled, often fatally, when they break down into smaller pieces they are often eaten which is toxic.