This is a complex infographic about how the choices you make in selecting a bag affect the environment in a variety of ways.
The data here will show you that, at least according to the calculations by Australian researchers published in Packaging Technology and Science, paper isn't necessarily better than plastic. When they ran the numbers, Helen Lewis, Karli Verghese, and Leanne Fitzpatrick found that paper bags actually fared worse on most measures than even a plastic bag made with unrecycled material.
The best option, given their assumptions and estimates, was actually a reusable plastic PET—that's a type of plastic—bag.
But let me make things even easier for you: Reusing bags of any kind radically increase their efficiency. The more times you use a bag of any type, the better it is for the environment. Of course, some bags are easier to re-use than others, especially the ones built for that purpose. But most plastic and paper bags can also be re-used at least a number of times. And think about it: Every time you do that, you spread the material and energetic cost of making that bag over another trip.
So, in the paper or plastic wars, I think you can find true virtue not just in the material of the bag itself, but in the way that you use it.
Here's how we're defining the parameters you see in the graphic:
- Global Warming is a measure of the carbon dioxide or equivalent greenhouse gases created by the bag production.
- Oxidation is a measure of the methane or equivalent released by the bag production. Methane is also a greenhouse gas.
- Eutrophication measures the amount of phosphorous (or equivalent) pollution created by the bag production. These chemicals can throw of aquatic ecosystems if they end up in lakes or, say, the Gulf of Mexico.
- Land Use is an easy one. It measures how much land is needed for the production.
- Water Use is another easy one. It measures the amount of water needed for production.
- Solid Waste is, roughly, the trash generated by the process.
- Fossil Fuels is a measure (in joules) of how much oil, gas, and coal were used.
- Minerals is a measure of how many minerals of other kids were used in the bag process.