For many, the biggest decision you have to make when shopping is the very last – do you want your food to be wrapped in paper or plastic bags? The stores would clearly prefer to go with plastic bags. They’re cheaper, easier to store, and take up much less space compared to paper bags. Most people find plastic bags more convenient to carry groceries in, and they won’t break nearly as easily as paper bags, which appear to break when you look at them.
On the other hand, you know that plastic is not good for the environment. This plastic is used for 10 minutes, but for at least a thousand years. You could recycle the plastic bags, but few people do. You can use the plastic bags for other things, but the number of quantities required is limited. For all of these reasons, sometimes you pick one up for Team Earth and opt for paper bags.
If the paper handle breaks off, your purchases could spill anywhere, but at least you’ve done something good for the environment. Or do you have? Is our understanding of grocery paper and plastic bags based on facts or assumptions?
Examination of plastic bags
We make enough plastic bags to go around the world 63 times when lined up each year. That’s a lot of bags and it takes a lot of oil to make these bags. Some of the oil is burned to make the bags and some of the oil is made into plastic. All of the oil comes from fossil fuels, which use resources to get them from the ground.
As soon as we use the bags for a few minutes, the vast majority of the bags end up in the trash. These bags will still be on earth when your great-grandchildren have their own great-grandchildren and then this group has their own great-grandchildren (they will practically never go away). Some of these plastic bags are blown into the natural environment and harm wildlife. A dead whale was recently washed ashore and scientists found more than two dozen plastic bags in its stomach.
So why not just recycle the plastic bags? That’s not a bad idea except that it’s also quite expensive and the businesses that recycle it lose money. Since it is not a profitable operation, many recycled plastic bags are shipped to other countries and burned there. Recycling these bags probably isn’t as great as you thought.
On the positive side, plastic bags don’t take up too much space in a landfill when squeezed, and it costs a lot less money and resources to ship the same amount of plastic bags compared to paper bags.
Examine paper bags
Paper bags are much easier to recycle, but that too costs money and resources. Millions of trees are cut down every year just to make paper shopping bags. These paper bags take a lot more trucks to get them where they need to go. These trucks consume oil and actually end up using more oil than it takes to make and move the plastic bags. Researchers found that you would have to use your paper bag four times before it got better than using a plastic bag in terms of energy use and pollution.
The belief that a paper bag disintegrates much faster in a landfill than a plastic bag is also flawed. Landfills are designed so that materials don’t degrade over time. This is achieved by packing the garbage so tightly that no oxygen can get into the garbage. No oxygen means no breakdown. This is not a design flaw in the landfill. They do this so that the materials don’t disintegrate and then end up in our water supplies. So your paper bag is really not going anywhere in the landfill.
Of course, this one will be a breeze, right? Not so fast! Studies have shown that a new cotton grocery bag would have to be used 110 times before it uses less energy than a plastic bag. Sturdy reusable plastic bags would need to be used about 10 times before they break.
However, if you already own reusable grocery bags (which most people do) then of course you will get everything every time you use them. These bags have already been made so use them over and over again. Many of these bags are given away free of charge at conferences or other events. Use them, leaving out the plastic AND paper.
If you honestly take the time to think about how much waste we produce in disposable bags, you will find it ridiculous and incredibly wasteful. Keep your reusable bags in your car and actually use them. Try not to buy new reusable bags, use the ones you probably already have. Plus, many locations give you 5 cents refunds for using your own luggage. That said, if you use it 200 times you will … OK, don’t do it for the money – do it for the environment!
Mike Szydlowski is Science Coordinator for Columbia Public Schools.