Quietly, without much notice, the world’s population crept past the 7 billion mark on Oct. 31, according to the United Nations. The majority of people live on one continent, Asia, with two countries, China and India, accounting for almost 37 percent of the total.

What is striking is that while it took thousands of years for the population to reach the 1 billion mark — about 1830 — it took only 100 more years for it to hit 2 billion and, in the last eight decades, an additional 5 billion people were added.

In the past, there was a view that too large a population was a drag on economic growth. That certainly was behind China’s one-child policy, introduced by Deng Xiaoping after the death of Chairman Mao Zedong. Ironically, now, the world’s two most populous countries are also its most rapidly developing economies.

The rise of China and India show that a certain population size is necessary to achieve a critical mass for economic development.

In fact, economists project that India’s growth will outstrip that of China by about 2020 because, by then, the size of the Chinese labor force will have peaked while India will still have a young population, with a labor force set to grow to nearly a billion workers by 2050.

That is the demographic dividend at work: a rising proportion of people of working age along with a fall in the fertility rate. Output per capita rises during this window of opportunity, before an aging population lowers economic growth.

Of course, population size alone is insufficient for economic growth, as Mao proved during his long years as China’s supreme leader. An emphasis on politics over economics meant that the country’s working-age people simply did not have the opportunity to develop their potential.

Also, as professor Chu Shulong of Tsinghua University wrote recently, population growth “should also be accompanied by improvement of population quality at the same time, including education, skills, income and consumption. In that case, population growth can generate active effects for economic development.”

In the last three decades, the vast Chinese workforce, combined with low wages, was perfect for processing and assembly, and for attracting capital and manufacturing industries from both Asia and the West.

Of course this could not last, and there are many who believe that China is approaching — or has already passed -the Lewis Turning Point, when a surplus of cheap labor runs dry and employers turn to other low-cost countries.

The age-old struggle to get enough food to eat in China is reflected in the salutation that Chinese still use when addressing each other every day: “Have you eaten yet?”

As recently as 1995, the environmentalist Lester Brown issued a warning in an essay titled “Who will feed China?” He asserted that “food scarcity and the associated economic instability are far greater threats to security than military aggression.”

Ironically, while environmentalists worry about sustainability when contemplating a globe with 7 billion people, individual countries, such as Russia and Japan, worry about declining populations and what that means for the country’s economy and, indeed, its very survival.

Food sufficiency is not a problem for China today, but it is certainly true that the world’s 7 billion people cannot all live Western lifestyles. Already, automobiles fill the streets of China where once they teemed with bicycles.

No doubt, the Chinese would be healthier if they continued to ride their bikes and stuck to a diet dominated by vegetables rather than meat.

Andrew Sheng, former chairman of the Hong Kong Securities and Futures Commission and now president of the newly formed Fung Global Institute think tank, has pointed out that “the average Chinese and Indian cannot live the average American way of life without destroying our natural resources.”

That is simply common sense. Earth’s natural resources are simply insufficient. In fact, it would be a nightmare if ordinary Chinese and Indians started to live the American Dream. But how can anyone tell Chinese and Indians and others that the good life is reserved for Westerners and that they will never get to live it?

Can anyone morally justify a two-tier world, with first-class citizens in America and Europe and second-class citizens elsewhere?

This is not a case of pitting the developed against the developing world, the “haves” against the “have nots.”

Judging by the proliferation of the “We are the 99 percent” movements around the world today, unless its leaders get their act together, the people are likely to find new leaders who will.

Frank Ching is a journalist and commentator based in Hong Kong. Frank.ching@gmail.com Twitter: @FrankChing1

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