This isn’t normal: 2,000 years of economic growth

Graph of gross world product (GWP) historic, for the past two thousand years
Gross World Product (GWP) over the long term, 1 CE – 2015 CE

The graph above places our 21st century global economy in its long-term context. It plots Gross World Product (GWP), the global aggregation of Gross Domestic Product (GDP). The time frame is the past 2,015 years: 1 CE (or AD) to 2015 CE. The units are trillions of US/international dollars adjusted for inflation (converted to 1990 dollars). The main source is Angus Maddison.  Pre-20th century values are, by necessity, informed estimates by Maddison.

The year 1870 is marked with a white circle. In the millennia before 1870, the size of the global economy barely grew at all. Then, not long before the eve of the 20th century, all Hell broke loose. The most recent ten or fifteen decades appear in our historical economic record like an explosion. For perhaps 98 percent of human history, the economic trendline has been almost flat—horizontal. Over the past century-and-a-half it has been almost vertical.

The late-19th, 20th, and early 21st centuries have not been “normal.” They have been extraordinary and wondrous. Equally extraordinary is how far we have gone to normalize what is clearly an abnormal situation. Though our lifestyles and expectations are now tightly bound to near-vertical trendlines we talk and act as if nothing out of the ordinary is happening, and that we can count on more of the same for the foreseeable future.

Moreover, the 20th and 21st century exceptionalism on display in this graph is not limited to economic growth. Graphs of energy use, population, cotton or iron production, water withdrawals, food production, automobile numbers, air-travel miles, and nearly any other economic metric will look nearly identical to the graph above: millennia of little or no growth, then a sudden spike. There is upon the Earth a wholly new kind of civilization.

Graph sources: Angus Maddison, The World Economy, vol. 2, Historical Statistics (Paris: OECD, 2006) Tables 7b and 8b; and World Bank, “World DataBank: World Development Indicators: GDP at market prices” 

The Rule of 70

Graph of an exponential curve illustrating exponential growth and the Rule of 70.
16-fold exponential increase caused by a constant 2.8 percent growth rate over 100 years

This graph’s smooth curve shows how an investment, economy, population, or any other quantity will grow at a constant rate of interest or growth—that is, at a constant percentage. In this case the percentage is 2.8 percent, compounded annually.

In the graph, in year 0 the value is 1. Soon, though, the value is twice as high, rising to 2. It doubles again to 4, doubles again to 8, and again to 16. An economy or investment growing at 2.8 percent per year will double every 25 years. Thus, it will double 4 times in a century: 2, 4, 8, 16.

There is a very useful tool for quickly calculating the doubling time for a given growth rate: the Rule of 70. If you know the percentage growth rate and want to know how long it will take an initial value to double, simply divide 70 by the rate. In this case, 70 divided by 2.8 = 25. The value doubles every 25 years and therefor increases 16-fold in 100 years.

By the Rule of 70 we can calculate that a growth rate of 7 percent will cause an initial value to double in just 10 years. China’s economy has been growing by more than 7 percent since the early 1990s. If a value—the size of China’s economy, for example—doubles every 10 years, it will go through 10 doublings in a century: 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024. If China’s economy maintained a 7 percent growth rate for a century it would become more than 1,000 times larger. It is important to recall such facts the next time the Dow or some other economic indicator falls on the news that Chinese growth has “slowed” to 7 percent or less.

Exponential growth: US and Canadian GDP in the 20th century

US and Canadian Gross Domestic Product (GDP) historic
Canada and US Gross Domestic Product (GDP), 1900–2016

This graph shows the increasing sizes of the US and Canadian economies. The graph plots US Gross Domestic Product (GDP) on the left-hand axis, and Canadian GDP on the right. The time-frame is 1900 to 2016. The year 2000 is marked with an open circle, to highlight the 20th century. The units are trillions of US or Canadian dollars, and all figures are adjusted for inflation, that is, they are stated in 2016 dollars.

How much did these economies grow during the 20th century? US GDP in 1900 was $0.59 trillion dollars (in today’s US currency). In 2000, GDP was $14.3 trillion dollars—24 times larger. Canada’s economy in 2000 was 45 times larger than in 1900.

We can calculate the average annual growth rate. During the 20th century, the US economy grew at an average compound rate of 3.2 percent. We often hear growth rates of 2 to 3 percent described as normal. Indeed, if rates in the US or comparable nations fall below 2 percent, analysts warn of “slow growth.” Moreover, in recent years there has been consternation as Chinese economic growth rates have fallen from 9 or 10 percent per year to 7.

Can the US and comparable economies grow at rates in the 21st century that were “normal” in the 20th? Even if annual growth slows to an average of just 2 percent, the size of the US economy will increase 7-fold between 2000 and 2100. If the US economy grows at 2 percent per year throughout the 21st century, by 2100 the US economy alone will be more than twice as large as the global economy of 2000.

Growth rates of 2 or 3 percent per year, modest when considered over the short term, will, over several decades, cause an economy to double and redouble in size. Can we multiply the sizes of already-large national economies five- or ten-fold this century? Is it wise to try?

Graph sources: United States GDP: US Deptartment of Commerce, Bureau of Economic Analysis, NIPA Table 1.1.5; and Louis Johnston and Samuel Williamson, “What Was the U.S. GDP Then?” MeasuringWorth, https://www.measuringworth.com/usgdp/ . Canadian GDP: Statistics Canada CANSIM Tables 380-0566 and 384-0037; and M.C. Urquhart, “New Estimates of Gross National Product, Canada, 1870-1926…,” in Long-Term Factors in American Economic Growth, eds. Stanley Engerman and Robert Gallman (Chicago: University of Chicago Press, 1986)

Introduction to my blog, and to my forthcoming book

Welcome to Graphic Descriptions and my first post. Each week I will publish a new graph that will provide insights into the core processes, flows, energy sources, and transformations that underpin our immensely powerful, productive, and perilous 21st century civilization.

I’m interested in several questions, including, how did more than a billion of us come to live so well? What can history tell us about the future of our food and energy systems? Can we maintain “normal” 20th century economic growth rates through the 21st century? Is it wise to try? What can we learn from material flows within rainforests and coral reefs that will enable us to restructure our civilization so that it might be possible to keep some version of it functioning for hundreds or thousands of years into the future? How will our grandchildren heat their homes and charge their phones?

This blog is a companion to my forthcoming book. That book is complete and I hope that it can be published in 2017 or ’18. Like this blog, my book focuses on our global 21st century civilization. It explores our history, including the transformation of food and energy systems, with the aim of illuminating our future. If we do not understand how our 21st century civilization works, we can neither direct it, nor protect it.

I will post regular updates on this site regarding my book and its availability.

Welcome to Graphic Descriptions, and to a weekly exploration of the energy sources, processes, perils, and possible futures of the most powerful civilization that has ever existed on Earth.