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)