This column is about sustainability. A thought experiment, if you will. The numbers that follow may not be precise, in fact I’m quite sure they won’t be. But they will be close enough. Actually, I have no idea now close they are to safely call them accurate. But they will serve to make a point. 

For example, the world bank says there were 7.753 billion humans on the planet in 2020. Presumably, they counted the number of legs and divided by two to come up with this number. Using this as a base, they estimate that by the middle of this coming November the number will have increased to a nice round number, 8 billion, and a really, really round number of 10 billion by 2050.

Some scientists have apparently judged 10 billion to be the “maximum carrying capacity” for humans on the planet. No mention of how many giraffes, redwood trees, salmon or other species currently now occupying the planet will be there with us. Anyway, park the number 10 billion for a short bit.

According to the Energy Information Association (EIA) electric vehicles are expected to make up about one-third of the global fleet by 2050. Good news, but it also means that two-thirds of the 2 billion total vehicles on the planet’s roads and highways will still be running on internal combustion engines. 

Let’s assume (fraught assumption) that today’s global average number of people per household, five, will still be the case in 2050. That translates into 2 billion households.  

That’s enough numbers. What’s the point? 

When I started this column years ago, I chose the name “Per Capita Davis” to focus on the impact individuals can have on greenhouse gas reduction. Over time, I gravitated to placing responsibility for responding to the climate crisis on governments, and to some degree businesses. I still think this is the appropriate pathway, But I have found myself thinking lately not just about climate, but more broadly, sustainability. 

For example, the transition to electric vehicles will reduce the number of tailpipes, and that’s good news for the climate crisis, but there will still be 2 billion cars. What are the implications for sustainability of 10 billion persons, 2 billion cars, and 2 billion households? And not just cars, everything.

There are perhaps better words for this, but consider that the world as currently constituted consists of “Haves” and “Have Nots.” The Have Nots are reasonably pursuing joining the Haves. The Haves are not really interested in moving to a Have Less classification. So, demand for everything can be assumed to increase. 

Everything is made up of ingredients. These ingredients all come from a “supply chain” that resembles the famous matryoshka nesting dolls. Cars, for example, require some 30,000 parts (including small stuff like screws, nuts, and bolts) from as many as 4,000 suppliers. Everything has to come from somewhere and underlying any eventual car part is an ever-broadening pyramid of materials and energy to obtain, transport, and produce.

Tires are just one component of a car. To make a tire requires machines and lots of equipment. Other required inputs include natural rubber, synthetic rubber, steel, nylon, silica, and polyester. Not to mention “carbon black” a product of combustion of various petroleum products that is necessary for longevity of the tire.  Each of the inputs required to make a tire comes from a supplier that also requires parts and their own suppliers. The supply chain cascades until it meets raw materials which may be mined from the earth, or otherwise extracted from the planet’s natural resources. 

And, of course, cars and the process of making them has become more and more technically complicated. It used to be possible to open the hood of a car and work on the engine and rare earth elements were not involved in manufacture. Ah, for the good old days. Today’s cars are run by computers, and extraction of minerals has become a commercial stampede fraught with ethical and environmental issues.

It’s not just big-ticket items like cars, A more mundane example would be a Snickers Bar. The list of ingredients includes sugar, cocoa butter, chocolate, skim milk, lactose, milkfat, soy lecithin, peanuts, corn syrup, salt, egg whites, caramel and artificial flavors. And then, of course, there’s the packaging. Every ingredient will require its own cascade of supply chains.

The question I’m asking myself is how on earth do we define sustainability when there are 10 billion consumers of everything from cars to candy bars? The 2 billion households will create demand for air conditioners, refrigerators, food, lighting fixtures, rugs, stoves, curtains, couches, plates, hammers, hoses, garbage cans, computers, cell phones, televisions, books, art, diapers, water, clothes, toothpaste — the list is endless. Does the planet really have the resources for this? What does “carrying capacity” really mean?

Of particular concern is how all this consumer demand fits into the proposed 30x30x30 proposal that, in order to ensure our future, requires that we set aside 30 percent of the planet’s land mass and 30 percent of oceans and fresh water by the year 2030 if, going back to the giraffes, redwood trees and salmon, we have 10 billion people/consumers?

John Mott-Smith is a resident of Davis. This column appears in the print edition of the Davis Enterprise the first and third Wednesday of each month. Please send comments to johnmottsmith@comcast.net .