In the 1980s, when Deng Xiaoping committed China to the path of development, its strongest asset was its population. China was young and smart. Reaching 1 billion residents in 1982, the median person was in their low to mid-20s, making the country a perfect industrial workforce for a financializing West ready to offshore.

Four decades of applying it has made China rich, but the accompanying urbanization and population control policies have had a cost too. The median Chinese person is now 38 years old and projected to only grow older, nearly 50 years old by the mid-century. The new China is becoming old. This spells trouble for the future because as far as global power and prestige go, being young is at least as important as being rich.

It's also a problem faced by the entirety of the developed world, not just China. In the West, migration is the substitute for failing to raise native birth rates. Other regions remain young for now. Much of Africa maintains a median age of 20 years. Southeast Asia hovers between the late 20s and early 30s, and South America is at 32.

Each beats the US's median age of 38. But if birth rates plunge globally, migration is a partial solution that can only last so long and one that would have to be competed for. The battle for wealth and the battle for youth represent two axes of power. As far as the next few decades go, it's already getting clear who's going to win.

The Axes Using the two axes of wealth and youth, a simple model of the next few generations divides the globe into four emerging types of state economies. The rich and relatively young world of the metropole. The rich but geriatric old world. The older, economically stagnant, quiet world. And the relatively poor but currently high fertility young world.

We can intuit a number of their characteristics. With a relatively young and growing population and a high labor supply, the states of the metropole, primarily the United States, have what it takes to be a global economic power and a locus for immigration. But high gross productivity doesn't guarantee a particular per capita income and standard of living for its members.

It only has to be relatively wealthy compared to the rest of the world to have economic power, and moving there only has to make you relatively richer than home to be a migration hook. While the United States is poised to take the lion's share of this migration, other cities located in states with unfavorable fertility, like London or Moscow, will be regional migration hubs as well.

The so-called "first world" stretches both west and east of America, encompassing both Japan and Western Europe. But while they have similar levels of development, this old world has very different migration and fertility patterns from the US. Migration is lower, especially in Japan. In countries with high migration, like Germany and France, assimilation does not happen as easily as it does in America, and the native populations of these countries seem to have lower fertility than the national average.

All these countries are highly developed, and they experienced baby booms in the last century. They tend to have highly developed social welfare states and are dominant in global institutions. Collectively, these regions make up an old world which, in the near term, appears destined for a future of population aging, labor shortage, and slow or zero growth.

In parts that don't resort to immigration, governments are already attempting to manage this via technology and mechanization. It remains to be seen whether any will succeed at increasing their fertility, but countries with cultures of social cooperation and a strong sense of identity, such as Japan, will be interesting to watch.

The "quiet world" refers to the current "emerging market" states, many of which are on track to become older in median age than the US itself by 2050. Rather than "emerging," low future total fertility rates (TFRs) will likely doom places like Turkey, Ukraine, the Balkans, and parts of Central Asia to the "quiet world," in which an aging population cripples further economic development.

These countries differ strongly from each other in history and culture. Some had developed industrial national economies, others less so, but the fate of Europe's post-Soviet regions loom particularly large. While some have gotten richer in the past 30 years, emigration rates are extremely high among the young, and it is unlikely that most of these countries can complete a strong development track of the sort China accomplished.

Finally, we see the rise of a massive new category, the "young world," an untapped labor workforce of billions, particularly in parts of Africa, the Middle East, Southeast Asia, and South and Central America. Much of the offshoring over the last four decades did not reach these regions, although Chinese offshoring now is.

While much of the young world now lives in urban, semi-industrialized societies, hundreds of millions still live in rural regions. This population will be progressively incorporated into the world system of the metropole, as its current population ages out of their roles. The integration of these regions into production networks will be a major challenge given the extensive cultural differences, lower human capital, and lack of history with economic mobilization.

Social socialization takes a long time, sometimes generations, to complete. The Metropole Assuming current trends, the US of 2050 will have a median age of 41. It will be decisively younger than China and other East Asian states, and will edge out Iran, Turkey, Russia, Mexico, and even Brazil. The so-called "bricks" countries built a coalition on marketing themselves as part of a young, rising world.

In the battle of youth, the US will beat all except South Africa. Even more importantly, the US will have large and growing numbers of young workers, many more than other states of roughly similar median age. This will give the country a demographic edge over the so-called "emerging markets" of today, and its economic heft will only grow as its population does.

From the current figure of 332 million, the US population is expected to reach 400 million in 2058, at currently projected rates. The Census Bureau predicts continued growth throughout the entire 21st century, with the population projected to reach an immense 571 million by 2100. The number of people reaching military age annually isn't just a useful statistical measure of both military manpower, it's also an indicator of annual workforce growth.

In order, the top 10 countries ranked by this metric are currently India, China, Indonesia, Pakistan, the US, Nigeria, Brazil, Bangladesh, Ethiopia, and the DRC. In a practical sense, these are the largest 10 countries on earth. In the future, the US is the only already rich country that still appears in the global top group on this sort of manpower comparison.

The increase in both total population and young people will be heavily driven by international immigration. After 2030, net immigration is expected to overtake the natural increase of residents as the prime driver of population growth. By 2060, net immigration is expected to be double the annual natural increase, adding over 1 million people per year.

Population is unquestionably the key factor in suppressing the process of population aging and workforce decline. According to the US Census, "In 2016, about 78% of the foreign-born population was of working age, between 18 and 64 years, compared with just 59% of the native-born." This will expand the size and relative power of some demographics, such as Hispanics in the US.

It's likely that the current major cities will retain their place and prestige. Given that cities will attract the bulk of this migration, the battles between residents and newcomers will almost certainly magnify. Both the adversarial use of zoning, which can already be seen in current development battles, and more violent conflicts between classes and ethnic groups will likely occur.

It's also likely that current upper-middle class remnants within a number of cities will finally get pushed out or reduced to the professional renter class. However, some cities may figure out the right mix of building and law enforcement that stabilizes them into high-growth cities with minimal or ghettoized social conflict.

In these cities, each year's cohort of young workers will be larger than the last. The total number of persons under 18 in the United States is projected to continually increase, going from approximately 74.0 million today to 80.1 million in 2060. Many will be absorbed not only into the professional classes.

One of the traits of the metropole is that it is generally good for individual people as economic actors, but generally bad for population groups in terms of fertility and cultural continuity. Migrants from the young world will improve their own individual situations, but, like previous generations of migrants, will likely see fertility decline when faced with the social and economic pressures of the metropole cities.

Overall, this inflow will benefit the employers of large industries like agriculture that can handle high turnover, as well as those with the resources to continually retrain new entrants into not just their company, but broader US professional norms. In practice, it's likely that as cultural commonality declines, coordination within companies will become increasingly difficult to do well without an extremely strong set of internal norms and rigorous enforcement.

Particularly hard to resolve will be ethnic conflict along lines that are hard for US culture to perceive and regulate, such as the caste discrimination that already occurs in Silicon Valley. Despite the inevitable conflicts that will play out at the middle and lower levels of metropole society, there are clear beneficiaries in its power structure.

The US economy is already set up to favor large globalized companies with offshore production and onshore logistics and management, and US political elites share close ties with these industries. It's the outcomes of current political battles, not economic ones like wealthy tech billionaires versus DC regulators or competing energy lobbies, that will determine who wins access to the resources of the metropole.

The process of creating a metropole via demographic replacement will create strong growth of total GDP, with the related effects of strong asset appreciation and, particularly, the consistent growth of real estate values. This will benefit pre-existing holders of power and wealth above all else. In contrast to the US, members of the old world will generally have continually shrinking workforces, with each year's cohort of workers being smaller than the one before.

This differentiation is more radical than would be suggested merely by median age figures. Even with the much-publicized immigration and refugee influx into Germany, the German workforce is currently shrinking at the rate of 300,000 people per year due to retirements, and the annual labor shortfall is expected to reach a staggering 650,000 by 2029.

Statistics like this clearly show that the US is no longer even in the same category of country as many of its purported first world peers. The process of transition to a metropole is frequently characterized as a national collapse by commentators who erroneously conflate the global power of a state with the disruption of individual living standards for the lower and middle classes.

Indeed, it would appear that the decline of human development indicators may be an integral part of the metropole's power. While this process increases gross GDP and national power, large swathes of the metropole population could, and likely will, see falling life expectancy, increased child poverty, rising crime rates, and unaffordable housing.

The metropole begins as a first world country, with all the wealth and infrastructure that implies. However, these first world conditions appear to inevitably lead to very high labor costs and a shrinking workforce due to low fertility, population aging, and welfare programs reducing the imperative to work. The logic of the metropole is that it dramatically short-circuits this process by implanting something resembling a lower-cost, emerging market workforce directly into the existing structure of a formerly first world country.

To a large extent, the entire economic point of this process is to maximize gross GDP and world power by reducing wage growth, which is done by compelling the native population to compete with a hungry workforce of first and second generation immigrants. An optimistic view sees this as a viable, large, moderate-cost workforce, integrated into the pre-existing expertise, population, and resources of a first world country.

This will allow a mix of resource exporting, a degree of high-value technical exports, and huge amount of white-collar work in finance, logistics, software, and similar industries. The massive agricultural capacity of places like the Mississippi Basin will continue to provide huge volumes of grain for export. A more pessimistic view would suggest that the level of disruption and population replacement involved in this process will more fundamentally erase the inherited advantages of the existing first world nation, leading to serious instability or deterioration of technical capacity.

But even in relatively more pessimistic projections, it is hard to picture how a state with a population of 500-700 million and potentially the world's largest GDP would fail to be one of the world's preeminent geopolitical powers. The US capacity for energy independence is a particular advantage for its role as a metropole.

The considerable domestic production and reserves of oil, gas, and especially coal will fuel US industry and agriculture. If current trends hold, there will not be any other large, young, and wealthy power on earth in this century other than the United States. The Old World By the mid-century, the cumulative effects of aging and low fertility on currently wealthy countries in Europe and East Asia will become apparent.

The old world countries are those whose populations age and shrink due to low immigration and fertility. Their populations are on track to plunge below the levels of the period in which these countries became rich to begin with. In the decades ahead, they will face an entirely different social and economic trajectory than the United States.

Japan's current population of 128 million is projected to drop to 86.7 million by 2060, and its already advanced median age is predicted to increase to 53 by 2050. Germany's population of 83.2 million will fall to 74 million by 2060, with the median age increasing from 44 to 51. Italy's population of 60.7 million is expected to drop to 58.6 million by 2050, and 53.7 million by 2065.

Its median age will increase from 43 to 50 by the year 2050. South Korea will fall from 51 million to 44 million in 2060, with a stunning increase in median age from 38 to 53 by 2050. By way of contrast, the US median age will rise to only 41 by 2050, with France and the UK both at 42, and all three will have population growth rather than shrinkage.

However, outside of their capital cities, France and the UK lack the natural resources and overall populations to match the power of the US itself, making them something like bridge countries between the metropole and the old world proper. Countries with median ages in the 50s are entirely unprecedented, and no one really knows how a country in this situation will continue functioning.

In the most affected countries, more than 35% of the total population could be over 65 by 2050. Obvious effects include a drastic fall in geopolitical importance, stagnant or declining asset and real estate valuations, shortages and high prices of all forms of labor, and permanently falling or stagnant GDP. Due to current high levels of wealth, health, education, and infrastructure, these countries will probably maintain statistically higher levels of individual human development and well-being for the foreseeable future, in a manner decoupled from their collapse in global importance.

Life in these places might be quite pleasant for the younger people due to a profound lack of competition for housing stock and the ability to demand extremely high wages for non-mechanized human labor jobs. As far as its role in the world system led by the metropole, the most obvious role of the old world may be recreational and aesthetic, particularly as a playground for the more privileged classes of the metropole and the young world.

The beauty and natural value of these lands in the eyes of outsiders will only be enhanced by the general slowing of activity and industry. Also, much of this area has great agricultural potential as well as an increasingly vacant countryside, raising the potential of expanded export agriculture using some form of guest worker labor from the young world.

Further potential lies in the deep linguistic and cultural links that some of the old world nations retain with their former colonial possessions in the young world. A number of these old world countries still provide managerial, financial, and more advanced manufacturing services to their former colonial possessions, acting as a sort of back office for the young world.

However, there is a danger that life in the old world will create a profound psychological malaise that only accelerates the process of degrowth and population collapse. What does it do to the human mind when you live in comfort, but there is no apparent future and nothing for your civilization to do but curate the relics of the past?

Life in many parts of the old world will mean not hearing the voices of children in the now empty park outside your window. Most of the teens and young adults you will see on a daily basis will be tourists, immigrants, or foreign guest workers. It may be that talented young workers from the old world emigrate to the metropole, or even the young world due to emotional rather than economic factors, out of the sheer desire to be where things are happening.

Given the high living standards for young people who do grow up in the old world, it might seem like there should be higher migration to it from the metropole. For those tired of a highly competitive life in the cities, a quiet existence in an aging welfare state might even sound idyllic.

But while such migration happens even now, there are many barriers to American migration to Europe or East Asia. The sheer logistics of formal immigration in these countries can be difficult, and most Americans face both cultural and linguistic barriers. For countries like Japan, permanent residency is extremely difficult to achieve, and most foreigners will never become citizens.

The fact is that the majority of people in any country, even those of the young world, will never even attempt to emigrate. Those who do will be a relatively small and privileged class with the ability to overcome these barriers. The ties of language and culture are strong, and the metropole has ample opportunity within its borders for the ambitious.

The longer game for these places is, in a sense, mysterious. Current trends are inexorably leading towards total fertility rates below one child per couple. Each new generation, pre-migration, is now approaching half the size of the prior, and the degree of shrinkage and aging discussed in this article appears inevitable, since even a deep cultural change to combat the momentum of this process would take decades.

One could speculate that these nations might eventually evolve a new cultural form or new subpopulations that have the ability to maintain above-replacement birth rates while living a fully technological developed existence, but there is little evidence of this to date. One might also predict mass incursions amounting to an invasion of these weak and dormant lands from the young world.

These nations still have the power to repel mass migration, but they may not choose to do so. The Quiet World In contrast with the old but rich world, there is the quiet world, and the related concept of the BRICS countries. These states are generally on a track to become old before ever approaching first world levels of wealth and development.

Rather than first world equivalents, this quiet world seems fated to spend the middle and later 21st century as lower middle income countries with the average person being middle aged. In comparison, by 2050 the United States will socially be closer to our image of an emerging market than the formerly emerging countries of this quiet world will be.

The demographic situations in China and Russia are well known, but it is very interesting to examine some of the smaller emerging markets, which most people casually assume to be fast growing, youthful places. By 2050, Brazil will have a median age of 44, similar to modern day Italy. Turkey will have a median age of 42 by 2050, similar to Spain today.

Iran and Mexico will also have a median age of 42 by then. All either match or even exceed the US in age by this point in time. Developers of South and Southeast Asia may even join this category near the end of the century. Both Indonesia and India will have a median age of approximately 37 by 2050, similar to the modern United States.

However, even India is projected to begin experiencing significant population loss and unfavorable ratios of pensioners to workers after 2050. The tenor of life in this coming "quiet world" is hard to predict. What might life be like in a Turkey or Mexico that has the sleepy, elderly-heavy demographics of present-day Spain or Italy but without the high incomes?

The most obvious example of fairly old and poor countries existing today are some of the post-Soviet areas, such as Ukraine with a median age of 41.2 and pre-war per capita GDP of 3,726 US dollars. The economic impasse of poor countries too old to generate growth will become a major global issue far beyond the old Eastern bloc.

On the other hand, many of these countries are major exporters of petroleum and food grains, and it is possible that increasing values for such commodities combined with stable populations might allow for reasonably comfortable conditions for these aging populations. The speed of manufacturing transition towards the young world may also become an asset for those able to integrate into the new supply chains.

Given their current economies, Mexico and Turkey have the capacity to maintain but not to increase their manufacturing and assembly operations, particularly in complex fields such as automotive, shipbuilding, aviation, and armaments. But no major emerging market country has the capacity to actually emerge as a leading world power or seriously challenge the United States in the post-2030 period.

With the exception of India and its delayed trajectory, their maximum geopolitical power and influence have probably already peaked. The Young World As the First World plunges towards median ages in the 50s, most of Africa still has median ages under 20, with Niger the lowest at only 14.8 years. Outside of Africa, there is still a significant young world as well, including Palestine at 18, Afghanistan at 19.5, Yemen at 19.8, Iraq at 21.2, Pakistan at 22, Guatemala at 23, Jordan at 23.5, Syria at 23.5, Egypt at 24, and Honduras at 24.

Much of this young world will retain median ages of under 30 years old to 2050 or beyond, similar to Mexico today, while traditional cheap labor countries such as Thailand and China age into their 50s and presumably become non-viable for high labor production. The new cities of this young world will be vast, turbulent, and often violent, as has always been the lot of young and fast-growing cities.

In 2050, the DRC's Kinshasa will have 35 million, Lagos will have 32 million, and Karachi will have 31 million inhabitants. The raw demographics that compel this outcome are essentially already in place. Barring some unprecedented global collapse, the young parents of Lagos in 2040 are already alive now. The future of this young world will likely be characterized by a rolling frontier of manufacturing and other high-labor enterprises, quite possibly including large agricultural and natural resource projects.

This is an attractive option for current rich countries, but it also requires a workforce willing to venture into the young world and oppose the physical and logistical discipline of industrial economies in these regions, a process China is carrying out across many regions today. Creating an industrial workforce is immensely difficult.

It required a full mobilization of society in Europe and America, from mass public schooling and factory discipline to negotiating institutions between employers and workers. The process will likely look similar to what occurred in Mexico, where a very poor, almost entirely agrarian nation gradually developed into a hub of industry and commercial agriculture, which now supplies much of America's vegetables and assembles our highly complex computerized cars and trucks.

Both US and Mexican companies carried out the process with state backing. Airports in the least developed African states provide another example of maintaining advanced infrastructure in areas without human or physical support systems. You can fly from Omaha, Nebraska to Jemena, Chad within a day and a half on commercial passenger jets with no extraordinary difficulty.

But the radar, control systems, jets, and everything else involved in operating a commercial airport in Chad are imported wholesale. The airport is de facto under the control of French Air Force officers, although the personnel you encounter when arriving are trained native Chadians. The frontier is rolling because the metropole and the old world do not necessarily outsource to the least developed, youngest, and lowest labor cost locations.

There is very little export manufacturing in the least developed and theoretically cheapest countries of sub-Saharan Africa due to their critical lack of infrastructure and human capital, not to mention populations that may be entirely unaccustomed to routine wage labor or mechanical processes. However, the goal is to strike an ideal balance between low labor costs and minimally adequate infrastructure and workforce development.

The development of this vast new economic frontier will likely move roughly in order of higher to lower median age and higher to lower development. This is because the very youngest countries, without exception, are either extremely underdeveloped, engaged in civil war, and disorder of a type that precludes foreign investment, or both.

Historically, as in China and India, foreign investment for export appears to gravitate towards countries of the median age in the early 20s versus the mid-teens seen in much of Africa. A key example of a country that was too young is Ethiopia. Much was made in the financial press of Ethiopia as one of the next big emerging markets, but the country has recently descended into a period of open-ended civil war with up to 500,000 total deaths to date.

This is not so surprising if we consider that Ethiopia's current median age is 19.5. This age increased from 16 due to the early stages of modernization, but Ethiopia blew up right as it approached age 20. As costs continue to rise in India or Thailand, attention in Asia will likely shift to Pakistan or Egypt.

At a certain point, conditions will suggest an extension of operations from Pakistan into Afghanistan. China is already courting its new government, and from Egypt into Yemen or Iraq. From there, the more developed African states, such as Sudan and Nigeria, are a logical choice. It may be late in the century before attention seriously turns to the last frontiers of labor, such as Mali, Chad, and the DRC, for ventures other than mining and resource projects.

The New Frontier Like 19th century Europe, the US seems on track for stricter internal competition for space and opportunity. California provides a rough preview of domestic conditions as it approaches 2050. By any objective numbers, California is incredibly rich, nationally dominant, and very far from collapsing. It has high asset prices, enormous agricultural production, and a very large population that has grown steadily over the past 50 years.

It has not just the largest economy by far of any US state, but also the fifth largest economy in the world at $3.36 trillion, versus Texas at $1.99 trillion and New York at $1.85 trillion. California attracts large numbers of legal and illegal immigrants from every corner of the earth, many from the young world.

The increasing amount of residences with ties to the young world and other parts of the globe give it an outward-looking culture. Yet California is becoming famous for exporting native-born Californians. In the midst of its affluence, many natives have fled, finding that extreme asset prices and competition with a constant stream of new immigrant workers render it impossible for them to make the sort of life they desire in their native land.

California presents a situation of simultaneous immigration and displacement, even as it grows larger and richer. As much ire as California draws, it doesn't stop drawing people. Even many who leave end up coming back or maintaining business ties. And the metropole has the priors for a similar kind of term-setting power in its relationship to the other spheres of the world.

Rather than multipolarity or decoupling, the hard realities of age and wealth will add up to a system of global power that, in many ways, looks very familiar.