One of the most rightly celebrated books of the early environmental movement was New Yorker writer John McPhee's 1971 page-turner, Encounters with the Archdruid. The quasi-religious figure referenced in the title was naturalist legend David Brower, the first executive director of the Sierra Club and founder of a half-dozen other environmentalist organizations, including Friends of the Earth and the League of Conservation Voters.

McPhee's concept was elegantly simple: Send Brower out into environmental no-man's lands with his antagonists—a mining magnate in the Glacier Peak Wilderness area, a golf-loving real estate developer on Georgia's Cumberland Island, and United States Bureau of Reclamation Commissioner Floyd Dominy on the Colorado River, which Dominy had recently helped disfigure with the Glen Canyon Dam. Brower was a larger-than-life figure, by turns prickly and pragmatic, conversational and condemnatory; yet his opponents on these trips also viewed themselves as responsible stewards of Mother Nature, and the ensuing repartee is a fascinating collision between mid-century faith in engineering progress and the first stirrings of a more pessimistic countercultural backlash.

Yet the anecdote from the book that sticks out most to contemporary eyes is a literal throwaway line about McPhee himself. Brower, Dominy, and the author are floating down the Colorado, opening up cans of beer in the hot sun. "They put the aluminum tongues inside the cans," McPhee writes. (For those of you under 35, these were the bits that you had to rip off a can in order to get at the deliciousness within.) "I threw a tongue in the river and was booed by everyone."

Here was the man widely considered to be the best long-form environmental journalist of the past 50 years, just hucking trash into an endangered river under the watchful eyes of the 20th century's leading Friend of the Earth. An act that seems almost deliberately shocking to our modern sensibilities—like the scene in the first season of Mad Men, in which the Draper family ditches the detritus of a lovely picnic lunch onto a grassy knoll—was presented in 1971 more as a commentary on the extreme pieties of oversensitive nature lovers. Unwittingly, this passage might be the best literary rendering of a concept too little understood in our sky-is-falling culture: the environmental Kuznets Curve.

In the 1950s, the Belarussian-born American economist Simon Kuznets hypothesized that income inequality as a nation industrializes can be shaped like an inverted U—it increases in the early stages of growth, reaches an apex, and then starts tapering down as the economy matures. The switch begins to happen after a critical mass of people abandon farm life for the big cities, where they obtain better education, benefit from economies of scale, and start agitating for policy changes.

Ironically, at a time when Kuznets' original concept has come under intensified attack in the inequality-obsessed developed world, its application to the environment has gained considerable purchase both academically and observationally. As Science Correspondent Ronald Bailey traces in "The End of Doom" (page 20), many of the woes that people still assume are getting worse are actually improving in the most advanced countries.

The richest nations are reforesting, not deforesting; cleaning up rivers and skies instead of making them dirtier; beating back cancer instead of contributing to its increase. As women get wealthier they gobble up educational opportunities and gain control over their own reproduction, to the point where the fertility rate of Mexican women will soon plummet to replacement level. Some nostalgiacs may lament the disappearance of the family farm, but the swapping out of subsistence agriculture for city life is a net plus for the environment and a net boon for the participating migrants.

Some of the virtuous Kuznets action in the rich world can be attributed to sheer technological progress. Cutting-edge technology, from agribusiness to apps, always seeks to produce more output with less input. Other advancements can come from the types of regulations that an increasingly wealthy populace demands—a desire to see the mountains in Southern California leads to the prohibition of leaded gasoline, for example.

But arguably the most important change is the one hardest to measure: that which occurs first within the human heart, then in behavior. If you look around at the world, and even at your own life, you will see examples of the Kuznets Curve all around you.

The most widespread practice of self-pollution—cigarette smoking—is down all over the developed world (while rising in industrializing countries such as China and India). A quarter-century ago, being in a bar almost anywhere on the globe meant stinging eyeballs and reeking clothes; now you can't even smoke in a bar in Paris or Prague. (Save for the moment your objection to any given government policy—I am enough of a hard-ass about smoking bans to have once led a protest against one—and instead concentrate on observable environmental and health improvements.)

When I first visited Italy in 1990, there wasn't a single beach that didn't feature a tide line speckled with tossed cigarettes and abandoned Fanta bottles. Strolling on Italian beaches in the summer of 2015, I saw nothing of the sort. In 1997, I shuddered with horror as an acquaintance of mine—a member of the Macedonian Green Party, no less—blithely tossed out of our car window an empty battery package into an ecological reserve. Nearly two decades of comparative prosperity later, I'm confident she would do nothing of the sort. We no longer need public service announcements with faux Indians crying at the sight of roadside litter; now we all cry, or at least most of us above the poverty line in the West.

In the twilight struggle over environmental policy, combatants on either side often become almost monomaniacally obsessed with the affiliation and presumed evil intent of their opponents. For many in the free market camp, new greens are just old reds, seeking to squeeze down the private means of production by the only politically viable mechanism left. Buttressing their argument are actual former Communists such as Mikhail Gorbachev transitioning without missing a beat to environmental advocacy, despite the brutally poisonous track record of really existing socialism; or the quick shift by the Naomi Kleins of the world from anti-globalization to anti–global warming.

For many on the environmentalism-advocacy side, those resisting this or that government regulation are doing so not out of principle, but from a mixture of know-nothingism, greed, and occasionally even an active desire to make the planet filthier. It's all a "race to the bottom," as demonstrated by whatever corporation-inflicted environmental catastrophe is making headlines this month. At the heart of this defilement is an original sin of man elevating himself to the top of the resource food chain. As David Brower himself once said, "Overpopulation is perhaps the biggest problem facing us."

But both sides may be missing the (renewed) forest for the trees. Yes, there will be, and should be, constant battles over the role and scope of government, as well as over the role and scope of industry. Concentrated power of any size seeks to acquire more of the stuff, fend off shackles, and suppress competition; the world is pockmarked with the deleterious results, including within walking distance of my Brooklyn home a canal so toxic that any large sea creature dies within hours of mistakenly swimming into it.

But moving the periscope back reveals a long-term trend toward environmental cleanliness everywhere that capitalism has been allowed to flourish at length, whether it be in democratic socialist France or the allegedly laissez faire United States. We all get there, as long as we don't totally murder the goose that laid these golden eggs.