I haven’t looked at population so far in this blog, and it is time I did. Population is among the most important environmental issues because humans have needs. We consume stuff to meet our needs, and when we do, we create waste. Sometimes it is the consumption itself that creates environmental stress, as when entire mountains are destroyed to mine coal. Other times, it is the waste that creates environmental stress, as when toxic chemicals resulting from industrial processes are dumped into rivers.

This allows us to understand a very simple, but very important principle: the total amount of environmental stress depends on how much stress each person creates and on how many people there are. You can express this as an equation:

Total environmental stress = per capita environmental stress x number of people.

If the number of people increases, total environmental stress will increase (unless the amount of stress each person creates decreases).

Throughout history, the population of the world has increased, with only a few, brief interruptions. However, world statistics are not the focus of this blog, Missouri is. The first graph at right shows the total population of Missouri and of the United States from 1900-2010. Total Missouri population has grown from about 3.1 million in 1900 to almost 6.0 million in 2010, a 93% increase. Meanwhile, the population of the United States grew from 76.2 million in 1900 to 308.7 million in 2010, an increase of 305%.

Population has not grown equally in rural and urban areas. The second graph shows population in Missouri divided into its urban and rural components. The urban population grew from 1.1 million in 1900 to 4.2 million in 2010, a 281% increase. Meanwhile, rural population actually declined from 1.9 million in 1900 to 1.4 million in 1970, then grew to 1.8 million in 2010, a 5% loss overall.

The third graph at right shows similar data for the United States as a whole. The urban population grew from 30.2 million in 1900 to 249.3 million in 2010, an astounding increase of 725%. Meanwhile, the rural population grew from 46.0 million to 59.5 million, an increase of 29%.

Unlike some of the graphs we’ve looked at, these graphs do not show lots of variability. The trend goes up, and it is remarkably consistent across a large number of years.

Thus, since 1900, population in Missouri has grown at 1/3 the rate it has grown nationally. In addition, both in Missouri and nationally, urban population has grown much more than rural population. Where in 1900, the rural population was the majority, now it only makes up 30% of the population of Missouri, and 19% nationally. When Thomas Jefferson imagined the United States as an agrarian utopia, I wonder if he imagined a country where 81% of the people lived in urban areas?

More on what this urban-rural change means for Missouri’s environment in future posts.

Sources:

The population data comes from 3 sources at the United States Census Bureau. I find their website to be the most difficult to use of all the websites I research. The problem is that the way they have measured population and published the data has changed over the years. Trying to find consistent data across all years can be maddening.

Urban and Rural Populations, United States, Regions, Divisions, and States: 1900-1990, Geography, U.S. Census Bureau, http://www.census.gov/geo/reference/urban-rural.html.

Table 29. Urban and Rural Population by State: 1990 and 2000, Statistical Abstract of the United States, U.S. Census Bureau, http://www.census.gov/compendia/statab/2011/tables/11s0029.pdf.

Percent Urban and Rural in 2010 by State, Lists of Population, Land Area, and Percent Urban and Rural in 2010, Geography, U.S. Census Bureau, http://www.census.gov/geo/reference/ua/urban-rural-2010.html.