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Centers of Progress, Pt. 12: Hangzhou (Paper Money)

Blog Post | Human Development

Centers of Progress, Pt. 12: Hangzhou (Paper Money)

Thanks to relative peace, far-ranging trade and cultural openness, Hangzhou prospered and produced many accomplishments, including inventions that we still use today.

Today marks the twelfth installment in a series of articles by HumanProgress.org called Centers of Progress. Where does progress happen? The story of civilization is in many ways the story of the city. It is the city that has helped to create and define the modern world. This bi-weekly column will give a short overview of urban centers that were the sites of pivotal advances in culture, economics, politics, technology, etc.

Our twelfth Center of Progress is Hangzhou in 12th century China, during the late Song Dynasty’s so-called premodern “economic revolution” or period of proto-industrialization. With its innovations in printing and manufacturing, it has been said that the “Song came closer to initiating an industrial revolution than any other premodern state.” The Song dynasty, which spanned from 969 to 1276 AD, was a time of dynamism and invention. Through trade and industry, the Song empire became the richest on Earth. The dynastic capital, Hangzhou, was the wealthiest and most populous city in the world. Song-era China became the first country to print paper money, which is far easier to carry in large amounts than metal coins. Hangzhou served as a money-printing center and a hub of innovation and creativity.

During the Song era, the average Chinese person experienced extraordinary growth in their income level as the economy expanded. The economy grew due to new technological and agricultural advances and efficient trade routes that produced a genuinely nationwide market. The era also witnessed a significant increase in international exchange, as Chinese merchants expanded their trade networks as far as East Africa. Growing wealth helped motivate the adoption of paper money, as people found themselves dealing with larger transactions than in the past.

Today, Hangzhou is one of China’s top commercial bases. It is also the southern terminus of the Grand Canal, which is the world’s longest artificial river and a UNESCO World Heritage Site. True to its rich history of innovation, Hangzhou continues to serve as a hub of enterprise. Hangzhou houses the headquarters of various Internet industry enterprises such as e-commerce giant Alibaba and is a growing technology center. Hangzhou is the heart of the “Hangzhou metropolitan area,” China’s fourth-largest metropolitan area by population, and is home to some 20 million people. Hangzhou is also a popular tourist destination within China. Hangzhou maintains many well-preserved cultural sites showcasing the city’s history. It even has a large history-based theme park—”Song Dynasty Town” or Songchen—filled with costumed reenactors portraying residents from the city’s golden age.

The Italian explorer Marco Polo famously described Hangzhou as “the most beautiful and magnificent city in the world” and called it the “City of Heaven” during a visit in the 13th century AD. While that was after the Song dynasty ended, much of the architecture and wealth of the city that Marco Polo observed was nonetheless a legacy of that era. (A statue of Marco Polo stands prominently in a lakeside park in the city, admiring Hangzhou’s beauty to this day). A common Chinese saying echoes Marco Polo’s sentiment: “Above, there is Heaven; below, there are Hangzhou and Suzhou”—the latter being another beautiful city just to Hangzhou’s north.

Hangzhou has been an important city since the 7th century AD when its Grand Canal was first built to connect the urban center to Beijing. Today, the canal remains the main north-south waterway in China. But the city’s golden age began when the Song dynasty made it their capital. The Song era saw the rapid adoption of woodblock printing, a technology that supercharged intellectual life in the Song dynasty. Hangzhou ranked first in China when it came to both volume and quality of woodblock printing. The technique, which consisted of carving text and pictures into wooden blocks, covering them with ink, and pressing the blocks against  paper, provided a way to mass-produce books, documents, and banknotes.

Woodblock printing developed in Buddhist monasteries to reproduce spiritual texts, with examples dating as far back as 200 AD, and the method was well-established by the 9th century AD. However, it was the Song era that first widely adopted woodblock printing for non-religious purposes. In the 11th century AD, the artisan and inventor Bi Sheng (990–1051 AD) devised movable type. The adoption of printing technology dramatically lowered the cost of books and encouraged the spread of literacy. Not only did widespread printing lead to a veritable tidal wave of artistic output such as poetry and dramatic texts, but it also sped up scientific progress—for example, by aiding the dissemination and advancement of pharmacological and medical knowledge.

If you could visit Hangzhou during its golden age, you would enter a gorgeous metropolis bursting with art, commerce, innovation, and a spirit of openness. The crowds would have been formidable; by the end of the Song era in 1276 AD, Hangzhou was home to around 1.75 million residents according to some estimates. That is slightly more than the current population of Phoenix, Arizona, but it represented an unprecedented urban concentration of people. While poor by modern standards, the city’s people were then the richest on Earth. Looking out onto the harbor, you would have seen large multi-sectioned ships with up to four decks and a dozen sails at a time when Europeans still traveled in tiny galleys powered chiefly by the muscle of rowers.

Thanks to advances in dyeing and weaving and textile industry developments, the city’s people would have worn a wide variety of beautiful and luxurious robes. You would not have seen many high-ranking women walking around. Despite the era’s many advances, it was also the beginning of “foot-binding” among China’s elite. That cruel practice consisted of repeatedly breaking the bones in women’s feet, starting in early childhood, to contort feet into an unnatural shape that was considered beautiful but made walking physically painful.

In the marketplace, you would see a food culture emerging that has since come to define Chinese cuisine. During the earlier Tang dynasty (the golden age of our tenth Center of Progress, Chang’an), China’s dominant grains were wheat and millet, and the most common drink was wine. During the Song dynasty, rice and tea became the country’s staple food and beverage and have remained so to this day.

You would have been mesmerized by the city’s elaborate architecture. (China’s traditional upturned roofs originated in the Song dynasty). Hangzhou’s striking temples, many of which still stand today, were a testament to the era’s philosophical and spiritual diversity. As writer Eric Weiner put it, “The blending of Buddhist and Confucian thought yielded a remarkably tolerant atmosphere.” Different thought-systems coexisted and thrived. Conversation rose to an art form, and as the city became wealthier, art of all kinds became an important part of everyday life. While in previous eras, poetry was limited to religious subjects, in the Song era, poetry expanded to deal with every topic imaginable, and poetry competitions were frequent.

Hangzhou was the site of great creativity. In the 11th century AD, the polymath Shen Kuo (1031–1095 AD) invented the magnetic compass. He also drew the world’s first topographical map and was the first person to record the process of sedimentation. Shen’s surviving notebooks have garnered comparisons to Leonardo da Vinci’s for their breadth. Shen’s work spanned topics such as mathematics, astronomy, meteorology, geology, zoology, botany, pharmacology, agronomy, archeology, ethnography, cartography, diplomacy, hydraulic engineering, and finance. Shen was also a prolific poet.

Another intellectual of the Song era was Su Tung-Po (1037–1101 AD). He was once a governor of Hangzhou but is better known for his art, work as an engineer, and insightful poetry. Tung-Po’s poetry reveals a self-effacingly unflattering view of government officials:

Families when a child is born
Hope it will turn out intelligent.
I … [o]nly hope that the baby will prove
Ignorant and stupid.
Then he’ll be happy all his days
And grow into a cabinet minister.

Given that many of the city’s advances came from the private sector, Tung-Po’s attitude was understandable. Even paper money was arguably a private sector invention. As early as the Tang dynasty (618–907 CE), the impracticality of transporting strings of heavy coins inspired Silk Road merchants to use paper promissory notes instead to make purchases. (Chinese coins had square holes in the middle to allow for stringing). Private agents originally produced those notes. At the beginning of the Song dynasty, the government recognized the value of that innovation and licensed deposit shops where people could exchange coins for such promissory notes, thus somewhat standardizing the system. Then, in the 12th century, the government gave still greater recognition to the concept of paper money by issuing the first official paper currency, called Jiaozi. Those banknotes often featured intricate illustrations of commerce.

During the golden age of Hangzhou’s “economic revolution,” the Song leaders managed to largely avoid international conflict by defusing tensions with trade agreements and tributary offers. Thus, Hangzhou was mostly at peace during its peak years, leaving its residents free to engage in enterprises that further enriched the city. “Between … 960 and … 1127 [AD], China passed through a phase of economic growth that was unprecedented in earlier Chinese history, perhaps in world history up to this time. It depended on a combination of commercialization, urbanization, and industrialization that has led some authorities to compare this period in Chinese history with the development of early modern Europe six centuries later,” according to the American historian Philip D. Curtin.

Factories situated in Hangzhou and the other major Song-era cities of Chengdu, Huizhou, and Anqi printed paper money with a uniform design using woodblocks and six different ink colors. Each city used multiple banknote seal stamps and different fiber mixes in the paper currency they produced to make counterfeiting difficult. In 1175 AD, as many as a thousand employees may have worked in Hangzhou’s paper money factory each day. The earliest money notes expired after just three years, and their use was limited to certain regions of the Song empire. Then, in 1265 AD, Hangzhou’s factories printed the first truly national currency. That currency exhibited a unified design, was accepted across the empire, and its value was backed by silver or gold. The paper money notes were available in various denominations. Unfortunately, that national currency was only used for nine years before a Mongol invasion ended the Song dynasty.

The concept of paper currency proved more lasting than the Song dynasty that created it. The subsequent Mongol Yuan dynasty issued their own paper currency, known as the Chao. However, the Mongols did not tie their currency’s value to anything and printed more and more banknotes until runaway inflation degraded the currency’s worth. Paper money can be susceptible to hyperinflation without sound monetary policy. Paper currency has nonetheless proved to be a lasting and practical invention that is now used worldwide.

For being a hothouse of invention and creativity and the site of an early economic revolution that gave the world paper money, 12th century Hangzhou is deservedly our twelfth Center of Progress. Bolstered by printing technology and paper currency’s efficiency, the Song era saw a steady stream of technological breakthroughs. Those included the compass, the first mechanical clocks, and the invention of forensic science. The economic and technological advancements of the Song era translated into improving living conditions for the average person. By practically every measure of human wellbeing, ranging from sanitation to literacy to average income, China was superior to Europe in the twelfth century. Thanks to relative peace, far-ranging trade, and cultural openness, Hangzhou prospered and produced many accomplishments, including inventions that we still use today.

Blog Post | Energy & Natural Resources

The Simon Abundance Index 2024

The Earth was 509.4 percent more abundant in 2023 than it was in 1980.

The Simon Abundance Index (SAI) quantifies and measures the relationship between resources and population. The SAI converts the relative abundance of 50 basic commodities and the global population into a single value. The index started in 1980 with a base value of 100. In 2023, the SAI stood at 609.4, indicating that resources have become 509.4 percent more abundant over the past 43 years. All 50 commodities were more abundant in 2023 than in 1980.

Figure 1: The Simon Abundance Index: 1980–2023 (1980 = 100)

The SAI is based on the ideas of University of Maryland economist and Cato Institute senior fellow Julian Simon, who pioneered research on and analysis of the relationship between population growth and resource abundance. If resources are finite, Simon’s opponents argued, then an increase in population should lead to higher prices and scarcity. Yet Simon discovered through exhaustive research over many years that the opposite was true. As the global population increased, virtually all resources became more abundant. How is that possible?

Simon recognized that raw materials without the knowledge of how to use them have no economic value. It is knowledge that transforms raw materials into resources, and new knowledge is potentially limitless. Simon also understood that it is only human beings who discover and create knowledge. Therefore, resources can grow infinitely and indefinitely. In fact, human beings are the ultimate resource.

Visualizing the Change

Resource abundance can be measured at both the personal level and the population level. We can use a pizza analogy to understand how that works. Personal-level abundance measures the size of an individual pizza slice. Population-level abundance measures the size of the entire pizza pie. The pizza pie can get larger in two ways: the slices can get larger, or the number of slices can increase. Both can happen at the same time.

Growth in resource abundance can be illustrated by comparing two box charts. Create the first chart, representing the population on the horizontal axis and personal resource abundance on the vertical axis. Draw a yellow square to represent the start year of 1980. Index both population and personal resource abundance to a value of one. Then draw a second chart for the end year of 2023. Use blue to distinguish this second chart. Scale it horizontally for the growth in population and vertically for the growth in personal resource abundance from 1980. Finally, overlay the yellow start-year chart on the blue end-year chart to see the difference in resource abundance between 1980 and 2023.

Figure 2: Visualization of the Relationship between Global Population Growth and Personal Resource Abundance of the 50 Basic Commodities (1980–2023)

Between 1980 and 2023, the average time price of the 50 basic commodities fell by 70.4 percent. For the time required to earn the money to buy one unit of this commodity basket in 1980, you would get 3.38 units in 2023. Consequently, the height of the vertical personal resource abundance axis in the blue box has risen to 3.38. Moreover, during this 43-year period, the world’s population grew by 3.6 billion, from 4.4 billion to over 8 billion, indicating an 80.2 percent increase. As such, the width of the blue box on the horizontal axis has expanded to 1.802. The size of the blue box, therefore, has grown to 3.38 by 1.802, or 6.094 (see the middle box in Figure 2).

As the box on the right shows, personal resource abundance grew by 238 percent; the population grew by 80.2 percent. The yellow start box has a size of 1.0, while the blue end box has a size of 6.094. That represents a 509.4 percent increase in population-level resource abundance. Population-level resource abundance grew at a compound annual rate of 4.3 percent over this 43-year period. Also note that every 1-percentage-point increase in population corresponded to a 6.35-percentage-point increase in population-level resource abundance (509.4 ÷ 80.2 = 6.35).

Individual Commodity Changes: 1980–2023

As noted, the average time price of the 50 basic commodities fell by 70.4 percent between 1980 and 2023. As such, the 50 commodities became 238.1 percent more abundant (on average). Lamb grew most abundant (675.1 percent), while the abundance of coal grew the least (30.7 percent).

Figure 3: Individual Commodities, Percentage Change in Time Price and Percentage Change in Abundance: 1980–2023

Individual Commodity Changes: 2022–2023

The SAI increased from a value of 520.1 in 2022 to 609.4 in 2023, indicating a 17.1 percent increase. Over those 12 months, 37 of the 50 commodities in the data set increased in abundance, while 13 decreased in abundance. Abundance ranged from a 220.8 percent increase for natural gas in Europe to a 38.9 percent decrease for oranges.

Figure 4: Individual Commodities, Percentage Change in Abundance: 2022–2023


After a sharp downturn between 2021 and 2022, which was caused by the COVID-19 pandemic, government lockdowns and accompanying monetary expansion, and the Russian invasion of Ukraine, the SAI is making a strong recovery. As noted, since 1980 resource abundance has been increasing at a much faster rate than population. We call that relationship superabundance. We explore this topic in our book Superabundance: The Story of Population Growth, Innovation, and Human Flourishing on an Infinitely Bountiful Planet.

Appendix A: Alternative Figure 1 with a Regression Line, Equation, R-Square, and Population

Appendix B: The Basic 50 Commodities Analysis: 1980–2023

Appendix C: Why Time Is Better Than Money for Measuring Resource Abundance

To better understand changes in our standard of living, we must move from thinking in quantities to thinking in prices. While the quantities of a resource are important, economists think in prices. This is because prices contain more information than quantities. Prices indicate if a product is becoming more or less abundant.

But prices can be distorted by inflation. Economists attempt to adjust for inflation by converting a current or nominal price into a real or constant price. This process can be subjective and contentious, however. To overcome such problems, we use time prices. What is most important to consider is how much time it takes to earn the money to buy a product. A time price is simply the nominal money price divided by the nominal hourly income. Money prices are expressed in dollars and cents, while time prices are expressed in hours and minutes. There are six reasons time is a better way than money to measure prices.

First, time prices contain more information than money prices do. Since innovation lowers prices and increases wages, time prices more fully capture the benefits of valuable new knowledge and the growth in human capital. To just look at prices without also looking at wages tells only half the story. Time prices make it easier to see the whole picture.

Second, time prices transcend the complications associated with converting nominal prices to real prices. Time prices avoid subjective and disputed adjustments such as the Consumer Price Index (CPI), the GDP Deflator or Implicit Price Deflator (IPD), the Personal Consumption Expenditures price index (PCE), and the Purchasing Power Parity (PPP). Time prices use the nominal price and the nominal hourly income at each point in time, so inflation adjustments are not necessary.

Third, time prices can be calculated on any product with any currency at any time and in any place. This means you can compare the time price of bread in France in 1850 to the time price of bread in New York in 2023. Analysts are also free to select from a variety of hourly income rates to use as the denominator when calculating time prices.

Fourth, time is an objective and universal constant. As the American economist George Gilder has noted, the International System of Units (SI) has established seven key metrics, of which six are bounded in one way or another by the passage of time. As the only irreversible element in the universe, with directionality imparted by thermodynamic entropy, time is the ultimate frame of reference for almost all measured values.

Fifth, time cannot be inflated or counterfeited. It is both fixed and continuous.

Sixth, we have perfect equality of time with exactly 24 hours in a day. As such, we should be comparing time inequality, not income inequality. When we measure differences in time inequality instead of income inequality, we get an even more positive view of the global standards of living.

These six reasons make using time prices superior to using money prices for measuring resource abundance. Time prices are elegant, intuitive, and simple. They are the true prices we pay for the things we buy.

The World Bank and the International Monetary Fund (IMF) track and report nominal prices on a wide variety of basic commodities. Analysts can use any hourly wage rate series as the denominator to calculate the time price. For the SAI, we created a proxy for global hourly income by using data from the World Bank and the Conference Board to calculate nominal GDP per hour worked.

With this data, we calculated the time prices for all 50 of the basic commodities for each year and then compared the change in time prices over time. If time prices are decreasing, personal resource abundance is increasing. For example, if a resource’s time price decreases by 50 percent, then for the same amount of time you get twice as much, or 100 percent more. The abundance of that resource has doubled. Or, to use the pizza analogy, an individual slice is twice as large. If the population increases by 25 percent over the same period, there will be 25 percent more slices. The pizza pie will thus be 150 percent larger [(2.0 x 1.25) – 1].

Board of Governors of the Federal Reserve System | Economic Growth

Income Growth Over Five Generations of Americans

“We find that each of the past four generations of Americans was better off than the previous one, using a post-tax, post-transfer income measure constructed annually from 1963-2022 based on the Current Population Survey Annual Social and Economic Supplement.”

From Board of Governors of the Federal Reserve System.

Blog Post | Human Development

1,000 Bits of Good News You May Have Missed in 2023

A necessary balance to the torrent of negativity.

Reading the news can leave you depressed and misinformed. It’s partisan, shallow, and, above all, hopelessly negative. As Steven Pinker from Harvard University quipped, “The news is a nonrandom sample of the worst events happening on the planet on a given day.”

So, why does Human Progress feature so many news items? And why did I compile them in this giant list? Here are a few reasons:

  • Negative headlines get more clicks. Promoting positive stories provides a necessary balance to the torrent of negativity.
  • Statistics are vital to a proper understanding of the world, but many find anecdotes more compelling.
  • Many people acknowledge humanity’s progress compared to the past but remain unreasonably pessimistic about the present—not to mention the future. Positive news can help improve their state of mind.
  • We have agency to make the world better. It is appropriate to recognize and be grateful for those who do.

Below is a nonrandom sample (n = ~1000) of positive news we collected this year, separated by topic area. Please scroll, skim, and click. Or—to be even more enlightened—read this blog post and then look through our collection of long-term trends and datasets.



Farming robots and drones

Food abundance

Genetic modification

Indoor farming

Lab-grown produce


Other innovations

Conservation and Biodiversity

Big cats




Other comebacks



Rivers and lakes

Surveillance and discovery

Rewilding and conservation


Culture and tolerance

Gender equality

General wellbeing


Treatment of animals

Energy and natural Resources



Fossil fuels

Other energy

Recycling and resource efficiency

Resource abundance

Environment and pollution

Climate change

Disaster resilience

Air pollution

Water pollution

Growth and development


Economic growth

Housing and urbanization

Labor and employment



Disability and assistive technology

Dementia and Alzheimer’s


Heart disease and stroke

Other non-communicable diseases



Other communicable diseases

Maternal care

Fertility and birth control

Mental health and addiction

Weight and nutrition

Longevity and mortality 

Surgery and emergency medicine

Measurement and imaging

Health systems

Other innovations



    Artificial intelligence



    Construction and manufacturing


    Robotics and automation

    Autonomous vehicles


    Other innovations


    AI in science


    Chemistry and materials