© Eric R. Pianka
In the U.S., one horsepower is defined as a unit of power equal to 746 watts, nearly equivalent to the English gravitational unit of the same name that equals 550 foot-pounds of work per second. One horsepower is a unit of power that equals the work done in lifting 550 pounds one foot in one second.
One manpower = a unit of power based on the rate at which a man can work; approximately 75 watts, or about one tenth of a horsepower. In other words, it takes ten strong men to do the work of one horse.
Fossil fuel is our energy slave: one gallon is equivalent to about 50 horsepower hours and will move a one-ton car 30-50 miles. And, at current US prices, a gallon of gas is simply way too cheap, costing only a little over two dollars. Just imagine having to push your car that far -- how many people would be required and how long would it take? Let's do a few simple calculations.
The 2017 Mercedes-Benz S-Class has an 8 cylinder engine and gets 25 mpg on the highway. This muscle car is rated at 523 hp, equivalent to more than 5,000 men. Big SUVs are rated at 400+ hp. So called "low" horsepower cars such as the Mazda Sport (A6) and the Chevrolet Cruze are rated at 184 and 153 hp. Toyota's Prius has a 120 hp engine. Even motorcycles use hundreds of horsepower units. Thus, all require the energy of thousands of men. Quite simply, we humans are energy gluttons. Our voracious and insatiable appetite for energy is doing us in. We must learn to live more frugally using much less energy.
One of the many symptoms of the human overpopulation crisis is that we now face serious energy limitations. Most people seem to think that we just need more energy, when in fact, we need to be more frugal in our energy use. People need to understand more about energy -- humans are not exempt from the laws of thermodynamics. Every time energy is used, waste heat is produced.
Earth can no longer dissipate the heat it receives from normal incident solar radiation fast enough to stay in balance (Hansen et al. 2005). Waste heat humans generate from burning fossil fuels and using nuclear reactors only adds insult to injury.
Humans are extremely versatile, and although we seem to think that we exist outside the laws of nature, we do not. We are Earthlings first and foremost, and space and other planets will always remain hostile environments for us. Until recently, spaceship Earth has provided us with a rather nice place to live. But now, Earth’s life support systems are failing . . . we have overpopulated the planet and fouled its atmosphere -- the resultant pollution is contributing to global weather change. Earth is warming rapidly -- ice caps are melting and ocean currents are changing. The polar jet stream is wobbling erratically. Polar bears and penguins are facing extinction and though many humans refuse to face the facts, we might not be far behind.