My cats, Pezz and Pizo, helping me write this blog. Photo by W. Hamilton
(Click on the following link to listen to an audio version of this blog … Scarcity Breeds Value
One of the foundational ideas in economics is the “Law of Supply and Demand.” In an article in a recent issue of Money Magazine (February 10, 2023) there was a concise definition of this law:
“The law of supply and demand states that if a product has a high demand and low supply, the price will increase. Conversely, if there is low demand and high supply, the price will decrease.”
Many ideas and concepts that pertain to economics and economic systems are also applicable to ecology and ecosystems. Let’s take this idea of supply and demand and see how it fits into the human-generated ecosystem in which most of us are living.
First, we need to change some of the vocabulary of the definition a little to make it fit into its ecological usage. Instead of “product,” we will use the more general term “factor,” and instead of “price,” we will use the term “importance.”
So, our “Ecological Law of Supply and Demand” would be phrased like this:
“If a factor is in high demand and low supply, its importance will increase. Conversely, if there is low demand and high supply, its importance will decrease.”
Photo by Common Good Compost, LLC
The “factor” that I would like to examine in this supply and demand system is the single-use plastic bag. Over the years, most of us have brought home very large numbers of these plastic bags from grocery stores, drug stores, take-out food restaurants and cafes, and almost anywhere that sold small to medium-sized things. Everything, whether it needed a bag or not, was stuffed into one of the plastic bags and then carried home. The bags accumulated in larger and larger bundles in hidden closets, utility rooms, garages or basements, even in homes like Deborah’s and mine where we refused bags whenever possible and for decades have used re-useable grocery bags!
There was a very large supply of plastic bags! And, fitting our Ecological Law of Supply and Demand, they didn’t seem to have much value or importance.
Think about these lightweight, billowy sacks: in 2015, 730,000 tons of plastic bags/sacks/wraps were made in the United States. Americans used 100 billion plastic bags per year (about 365 plastic bags per person per year!), and it took 12 million barrels of oil to make these bags! Only 13%, or so, of these plastic bags were ever recycled. The rest were dumped into landfills where it takes over 1000 years for the plastic of the bags to break down, or they ended up cluttering and clogging up terrestrial or aquatic ecosystems where wind and sunlight and the physical movements of water slowly shredded them into little pieces. The ocean, tragically, was the frequent end-destination for many of these bags!
Photo by E. Fox
Oceans are full of both macro- and microplastics. Macro-plastics, like plastic bags, (only account for about 10% of all the plastics in the ocean!), but they can be eaten by marine animals (as I mentioned when I wrote earlier this year about sea turtles, floating plastic bags look like the jellyfish prey that many seas turtles eagerly seek). These ingested bags can cause blockages in the sea turtle’s intestines and lead to a slow, painful death. Over one million sea animals (including mammals, fish, sharks, turtles and birds) die each year from eating macro-plastics debris (see Signs of Winter 8, January 26, 2023).
The micro-plastics, though, (which are defined as plastics in pieces that are less than 5 mm in diameter) make up more than 90% of the total plastic load in the oceans. These plastics get into the ocean from many possible sources. They can be blown in from the land by offshore winds, they can form in the ocean from the breakdown of macro-plastics, they can come directly from industrial sources and poorly maintained landfills, but their most common source is via the inflow of waste-water containing residues of ordinary consumer products (like health and beauty aids).
T. gondii cycts. CDC, Public Domain
Microplastics are found in every corner of the ocean and in almost every type of marine organism! A study published in Scientific Reports last year (April 26, 2022) described pathogenic organisms (like Toxoplasma gondii, Cryptosporidium parvum and Giardia enterica) sticking to the surfaces of the microplastic pieces. Their concentration on the plastics were many orders of magnitude greater than their concentrations in the surrounding sea water! As sea organisms ingest the micro-plastics they also ingest large quantities of these pathogens. These pathogens, then, can infect humans who eat these infected organisms. The World Health Organization has indicated that T. gondii, C. parvum and G. enterica are the likely causes of large numbers of previously un-classified human illnesses that have resulted from the ingestion of shellfish.
Plastics and in particular micro-plastics represent a very serious environmental threat to our marine ecosystems, and all of those plastic bags we’ve been using and accumulating are a very visible part of that threat! For that reason, many states are passing laws to limit or eliminate single-use plastic bags.
So far, ten states (California, Connecticut, Delaware, Hawaii, Maine, New York, Oregon, Vermont, Washington and New Jersy) have passed laws eliminating single-use plastic bags. Seventeen other states (including, as of January 1, 2023, my new home state of Colorado) have passed laws to reduce the dispersal of single-use plastic bags often by requiring that shoppers be charged for each plastic bag used. In Colorado, this charge is ten cents per bag. In January, 2024, Colorado will take their bag-use laws to the next level and completely eliminate the use of single-use plastic bags.
Photo by Divotomezove, Wikimedia Commons.
So, back to Supply and Demand: like most homes in Colorado, our initially large, stored supply of plastic bags is now, after four months of very low rates of addition and accumulation, starting to get quite small. We are starting to notice these bags much more clearly than we ever did because there is a little dark secret about these awful, polluting items : they are very useful! They can be used as liner bags for small trash cans, as trash bags in the car, as bags for disposing of used kitty litter, as bags for dog feces, as bags for just about any messy, trash-related item that you can imagine. They were also useful in many re-use situation (dirty laundry when you were traveling, transport bags for just about anything)! Let’s look at our Ecological Law of Supply and Demand: as supplies of a factor get low and demand for that factor grows, they become more and more valuable!
I find myself carefully brushing out and reusing single-use plastic bags. I was positively ecstatic when our take-out food last weekend came in two, brand new, absolutely clean plastic bags! These worthless, polluting bags have become, in their growing scarcity, a household treasure!
It is amazing sometimes how things work out!
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