In the previous posts we looked at food as part stuff. Food is the most collectively massive element in our usual interpretation of stuff and it takes energy to transport it and control the food environment (through refrigeration or cooling) during transit. But there are two other components of stuff that are massive and need transport every day – people and energy.
Personally I rebel at thinking of people as stuff and prefer to contemplate the movement of living human mass. In the United States the average weight of a man is 195.8 pounds or 88.9 kilograms while the average weight of a woman is 164.4 pounds. Every work day 158 million people go to work, per Statista, distributed as follows:
Car, truck, or van 85.4
Public Transport 5.1
Taxi, Motorcycle, or other 1.2
Work at home 5.0
For those who go by car, truck, or van (134.9 million), the average round trip commute is 32 miles, and 76 percent travel alone. This equates to 102.5 million vehicles or 3.274 billion miles per work day. Adjusting for carpools of 3 people per pool, the total becomes 3.62 billion miles. If the average mileage of each vehicle is 25 miles per gallon of fuel, it takes 144.8 million gallons of gasoline or diesel fuel per day. There are approximately 261 possible work days per year and a gallon of gasoline weighs 6.3 pounds (diesel weighs more). Running the numbers this comes to 456,000 tons per day or 119 billion tons per year.
To make it a bit scarier, the average driver in 2015 drove 13,474 miles. Again using the 25 miles per gallon and a total work force of 158 million, you get 539 gallons per driver or 85.2 billion gallons of fuel. This equates to 536 billion pounds per year or 268 million tons per year or 0.7344 million tons per day (using 365 days).
But how much human mass has been moved? Again only using the workforce in the United States, 47 percent women and 53 percent men in 2010 with an average of 181 pounds, 158 million people (the workforce), and 365 days you get 522 billion human mass tons. Pause for a hiccup. If people, for the most part, travel by car, truck or van that average 1.75 tons each (3,500 pounds) an additional 100 trillion tons of mass can be added. Of course, not every driver drives alone. Families and friends are involved. Clearly more than 158 million people rode in these vehicles, but the fuel consumption does not change, at least not significantly.
Another hiccup regarding back of the envelope calculations (or should I say back of the smart phone) such as these is using only commuting drivers (and employed workers) in the calculations. In 2016, per Statista, there were 222 million drivers in the United States or 1.41 times the number of workers. Using the mileage of the average driver and adjusting by 1.41, you get 120 billion gallons of fuel being consumed, 378 million tons per year or one million tons per day. You can also increase human mass movement proportionally. But let us just stick with the workforce pool.
Again, looking at the movement of people, we find that 0.734 million tons of fuel need to be distributed per day, not including the distribution of diesel fuel for the trucking. The distribution of food adds another 0.656 million tons of mass for a total of 1.39 million tons of gasoline and food every day, or 507.4 million tons per year. Compare this to the 522 billion (not million) tons of human mass per year. Clearly if we, as people, would stop moving around so much, we could significantly reduce our fuel consumption.
All of these numbers are fun to play with on the back of an envelope or your smart phone, but what do they tell us (or not)? Very little. Instead, go to Statista.com and look up gas and distillate fuel (includes diesel) consumption for the United States for 2017. Per the data for the transportation sector, which includes the moving of goods and people, the U.S. used 125.7 million gallons of diesel per day and 376.9 million gallons of gasoline per day. A gallon of diesel releases 22.38 pounds of CO2 when burned and gasoline releases 19.64 pounds. Doing the math and adding the results, you get 10.213 billion pounds of CO2 released daily or 3.73 trillion pounds per year. That is 1.864 billion tons per year. The US Energy Information Administration cites 1.709 billion tons per year, but adjusts by subtracting biomass and biofuels. Both are very large numbers. Are there alternatives?