The steam engine and its successors changed the world. Now, thankfully, the computer and its kin are changing it back.
Why do I say “thankfully”? Because the industrial age — ushered in by steam power and sustained by internal combustion, electricity and other technologies — was hard on our planet. Year after year, we took more fossil fuels from the earth to power our growing economies. We also dug out more metals and minerals, chopped down more trees, cleared more cropland, used more water and fertilizer, and exploited our world in countless other ways.
During the industrial era our population and prosperity increased exponentially, but so did our consumption of natural resources. By the first Earth Day, in 1970, it was clear to many that the planet couldn’t keep up with all that expansion. Eventually, it seemed, earth’s finite carrying capacity would be overwhelmed by our unchecked, exponentially increasing appetites.
The only apparent solution was to curb those appetites; either voluntarily, by embracing a philosophy of “de-growth” (which is the same as signing up for a permanent, ever-deepening recession), or via central planning and rationing.
So what happened after 1970? Except for a few temporary restrictions like gas rationing, most countries didn’t try to force a slowdown in consumption of natural resources or mandate that companies produce fewer material goods for the sake of the planet. The United States certainly didn’t.
Similarly, most Americans didn’t embrace voluntary de-growth. Economic and population growth may have slowed since 1970, but they certainly haven’t started shrinking. Instead, they’ve kept increasing at pretty steady exponential rates. The American economy is more than three and a half times as big as it was in 1970, and our population has increased by about 60 percent since then.

(CREDIT: John Thys/Agence France-Presse — Getty Images)
We must have also kept on consuming natural resources at an exponential rate, right? Wrong. Instead, something completely unanticipated happened: In America<strong>,</strong> our total use of many critical materials leveled off and then started to decline, even as the population and the economy kept growing.
The magnitude of these reversals is stunning. According to the United States Geological Survey, in 2015, America consumed 15 percent less steel than it did in 2000, 40 percent less copper and 44 percent less gold. Total use of timber was down a third, and paper down 20 percent, from their peaks.
If we zoom in on industries like agriculture, we see the same thing. The total tonnage of American crops has increased by more than 20 percent since 1992, but overall fertilizer use is down almost 20 percent, and 13 percent less water is used for irrigation.
Finally, America’s total use of energy has plateaued, even as growth continues. The American economy is about 20 percent bigger than it was before the Great Recession started, but in 2018 the country consumed only 0.26 percent more energy than it did in 2007.
How did we accomplish all this? How did we decouple economic growth from resource consumption for the first time in human history? By putting the digital revolution to work.
Consider the example of reduced materials use in railroads. In the late 1960s, the rule of thumb for railroads in the United States was that only 5 percent of boxcars could move on a given day. This wasn’t because the other 95 percent needed to rest; it’s because their owners couldn’t keep track of them. At the time, monitoring a fleet accurately across thousands of miles of track and hundreds of freight yards was essentially impossible.
Railroads relied on human spotters who would watch trains pass, and then phone or telegraph any sightings of a company’s rolling stock back to headquarters. Though this approach was labor-intensive, it still made good economic sense. Over time, however, these human spotters were replaced by digital tools for tracking rolling stock across the country. Today, railroads have close to constant visibility over their far-flung assets.
Progress is occurring not just in America. A similar large-scale “dematerialization” is also happening in other rich countries, such as Germany and the Netherlands. Lower-income nations are still building out their infrastructures and therefore use more materials year after year, but I predict they’ll soon start dematerializing, too.
Are the twin forces of capitalism and technological progress all we need to ensure that we’ll take better care of our planet? Absolutely not.
As every Economics 101 student learns, pollution is the classic negative externality — a cost that arises out of an economic activity but isn’t borne by the parties directly involved in that activity. Technologies and markets do a lot of things spectacularly well, but they don’t take care of pollution and other externalities on their own.
We need another pair of forces to enter the picture: public awareness of the dire problems caused by pollution, and a responsive government able to put in place and enforce smart measures for reducing it. These were the forces, for example, that led the United States to pass legislation to protect vulnerable animals from the reach of capitalism and technology in 1973, after the extinction of the passenger pigeon early in the 20th century and the near-disappearance of various other species emboldened the efforts of the country’s conservation groups.
I call capitalism, technological progress, public awareness and responsive government “the four horsemen of the optimist.” When they all ride together, they let us increase human well-being without increasing the harm caused to our planet. Thanks to them, we’re moving past our bad industrial-age habit of despoiling the earth as we grow.
We’re now entering a cleaner and greener second machine age, powered by the computer and its kin. The other three horsemen are necessary, but technological progress is the only one that can allow us to get “more from less” and better navigate a world of dwindling natural resources.
© 2019 Andrew McAfee. Distributed by The New York Times Licensing Group