“People are suffering, People are dying. Entire ecosystems are collapsing. We are at the beginning of a mass extinction,” child prophet Greta Thunberg announced through tears at the United Nations Climate Summit in New York City last month, “and all you can talk about is money and fairy tales of eternal economic growth. How dare you.”

Instead of deriding the stunt, as they might have, national leaders and the presumed cream of the international community clapped like trained seals eager for a fish treat.

“No one has explained to Greta that the modern world is complex and different,” Russia’s Vladimir Putin—to his credit—exclaimed scornfully. “People in Africa or in many Asian countries want to live at the same wealth level as in Sweden.” And in spite of UN antics, industrial technocracy has no intention of reverting to subsistence and chronic want, nor should it.

Having risen from 2.5 billion to 7.5 billion since 1950, world population growth is historically staggering. UN projections for 2050—one generation out—stand at 10 billion. That’s an astonishing four-fold growth in one century. The earth’s carrying capacity is by many accounts being tested. Yet climate change and world population are rarely correlated today, since critical appraisals cannot but point the problem finger at fertility in Africa and the Third World.

The global desire for the comfort, wealth, and security that the First World’s underclass take to be rights remains unquenched. Indoor plumbing and running water, air conditioning and heating, automobiles, refrigerators, and techno-goodies all have worldwide appeal. How to reconcile—or even move haltingly toward—sustainability given limitless human demands is a tough one, as is maintaining the infrastructure—electricity, gas stations, irrigation, and tax systems—to back up consumption.

The “global community” has limited ability to mandate what the English cleric Thomas Robert Malthus long ago called “preventive checks” on population overload. In 1798, Malthus wroteAn Essay on the Principle of Population. English thinkers at the time, including Malthus, feared that “indiscriminate charity” could lead to an army of paupers dependent on government handouts, and eventually to national bankruptcy. Moreover, Malthus warned, food supplies were expanding slower than was population. Without restraint, famine would eventually provide catastrophic “positive checks” on that population.

In the Malthusian spirit, half a century ago, population apocalyptics took off. Paul Ehrlich’s 1968 runaway best seller, The Population Bomb, forecast, “In the 1970s hundreds of millions of people will starve to death in spite of any crash programs embarked upon now. At this late date nothing can prevent a substantial increase in the world death rate.”

While notoriously off the mark, Ehrlich maintains that intensive agricultural techniques have simply deferred disaster. His forecasts of continued overfishing, global warming, urbanization, chemical pollution, and competition for raw materials are widely shared. Ehrlich remains a staunch statist and anti-capitalist. In a 2018 interview with The Guardian, he proposed “unprecedented redistribution of wealth” but observed that “the rich who now run the global system—that hold the annual ‘world destroyer’ meetings in Davos—are unlikely to let it happen.”

In 1968, the ecologist Garrett Hardin wrote his celebrated essay “The Tragedy of the Commons,” still widely studied in college classrooms. “It is clear that we will greatly increase human misery if we do not, during the immediate future, assume that the world available to the terrestrial human population is finite,” he insisted. One of the most eminent scientists of his generation, Hardin argued against population growth, and advocated birth control and forced sterilization.

Coming from the academic left, Hardin contended that humans acting rationally in their own interests would destroy the planet. He stood firmly for state controls and against immigration. Why would an overcrowded lifeboat—a rich nation—take on new members, he asked, risking those capable of survival? For such thoughts, the Southern Poverty Law Center calls Hardin a “white nationalist” who is frank in his “racism and quasi-fascist ethno-nationalism.”

Changing the subject, yet still in tune with radical environmental fashion, Susan Sontag declared maliciously, “The white race is the cancer of human history; it is the white race and it alone—its ideologies and inventions” that “threatens the very existence of life itself.” Africa’s population explosion today not only suggests Sontag was wrong, but moves remedial strategies about climate change and ecological balance in unwelcome directions.

Long-term continental growth rates are very uneven. Over the last 250 years, Europe’s population has doubled to 450 million, trimmed by two world wars. Since 1950, by comparison, in three generations, Mexico’s population has more than quadrupled to 130 million. (The nation has exported perhaps another 15 million to the U.S.) Africa is growing at an even faster rate.

Since 1950, Nigeria’s population has risen from 30 million to 200 million, and is expected to double again to 400 million. Lagos, now a city of 22 million, grows in every possible direction and pushes relentlessly at its arable edges. Since 1950, Nairobi’s size has soared from 140,000 to 14 million; Kinshasa’s from 200,000 to 12 million. Abidjan, Dar es Salaam, Conakry, Dakar, and other sprawling African conurbations exhibit the same patterns.

The heralded African middle class that seeks to emigrate to Europe or America comes of age differently from a middle class, in, say, Frankfurt or Boston. Some grow up with running water, closed sewers, and clean hospitals. Others—many more—live in fetid, barely electrified slums and endless urban shanties of corrugated metal with next to no public services. These are places where life—despite smartphones—is brutal, filthy, insecure, and drab.

Since 2010, at least a million Africans have entered Europe, and many millions more would like to. Few are equipped for their new residencies. Native-born Europeans by and large shun them. Some of these migrants are employed at menial tasks at the bottom of the labor ladder. Others become wards of the state or live as transients in an immigrant demi-monde. African migrations en masse into Europe are “almost too overwhelming to contemplate,” says a world-traveled London banker. The prospect is already a potent force in continental politics.

In a review of Stephen Smith’s The Rush to Europe, Christopher Caldwell provides an eloquent, candid appraisal of an “extraordinarily disruptive mass movement of labor and humanity from Africa to Europe.” This ongoing migration, Caldwell argues, can bring Europe no benefits. The fantasy of migrant enrichment is “rationalization for something that Europe is undergoing, not choosing,” Caldwell says.

And Africa is political dynamite. Just ask Emmanuel Macron, who in 2017 faced the subject with some grace and realism. Taking a question on why there is no Marshall Plan for Africa’s development, he responded, “The challenge of Africa, it is totally different, it is much deeper, it is civilizational today. What are the problems in Africa? Failed states, the complex democratic transitions, demographic transitions, which is one of the main challenges facing Africa.” His peers and the global media viciously slapped back, ensuring that Macron never again erred in his ways.

The population of sub-Saharan Africa is projected to double by 2050 from 1.2 to 2.4 billion, should fertility trends continue uninterrupted and world surpluses endure. But many nations worldwide are already dependent on a global version of “indiscriminate charity.” Free society abhors the idea of government-based eugenics and mandated private restraint that Malthus advised—and rightly so. Not surprisingly the Chinese have stakes in Africa’s future and fewer qualms than the West about imposed population control.

All the world should hope smart minds, not just in China but at the United Nations, World Bank, European Union, and U.S. State Department, are taking Malthus seriously. Nature is a powerful, ineffable system. It will be ready to curb biomass long before Greta’s fantasies of mass extinction come close to realization.

Gilbert T. Sewall is co-author of After Hiroshima: The United States Since 1945 and editor of The Eighties: A Reader.