Eight Inches

Imagine for a moment that the earth was reduced to the size of a basketball. Now imagine that part of the planet on/in which we “live and move and have our being.” Although the atmosphere gets very thin the higher you go, let’s consider the heights of aircraft at around 10 miles in altitude or 50,000 feet as the top. Then consider the bottom of ocean trenches at around 5-7 miles deep. From the height of aircraft to the bottom of the ocean is a layer of about 15-17 miles on a planet with a radius almost 4,000 miles.

Take twelve sheets of 20 # typing paper.  Each sheet is about .003 inches thick. Wrap them on your imaginary basketball-earth. That .036-inch layer of paper represents the 15 miles on our planet’s surface in which all of humanity lives, or tries to.  But it gets better.

The global average depth of topsoil on tillable land (non-mountainous) is about eight inches. There are exceptions. The rich, alluvial soils along the Mississippi River can be 1,000 feet deep. Along the Arkansas River in Oklahoma, the soils can be hundreds of feet deep. But in the desert, there is zero topsoil. It averages out to eight inches.

After the Civil War, various federal policies[1] incentivized white people to live in the Great Plains area. Many settlers in this vast influx believed in the erroneous superstition that “rain follows the plow.” Or that homesteading and agricultural development would permanently change the climate of the region. (Fact: It does permanently change the region’s climate, only for the worse by reducing rainfall and turning prairie into desert.) Connect the dots between the preaching of ministers and politicians of “American manifest destiny” (that white Americans had a sacred duty to expand to the west) and you have all the makings of a man-made climate disaster.

Add to this westward settlement the prospect of making a good living by farming. Rising wheat prices, lower cost trans-Atlantic shipping and increased European demand for wheat created a ready market. Farmers plowed and broke millions of acres of the Great Plains converting native prairies that stored the equivalent of five to ten FEET of water in the soil to cropland that stored only a few inches of water.

By 1931, drought set in. Crops began to fail exposing bare, over-plowed farmland. Lacking the deep-rooted native prairie grasses to hold the soil in place, the soil began to blow away leading to massive dust storms across the Great Plains and Midwest. Drought throughout the 1930s led to economic disaster. 35 million acres (seven times the size of this year’s fires in California) were rendered useless as the topsoil blew away. Another 125 million acres (3/4 the size of Texas) lost considerable soil depth. Rainfall returned by the end of the decade, but millions of Midwesterners migrated west to the promise of California.

Midwest dust storms sent black dust clouds swirling in New York City and Washington, DC. Ships sailing the Atlantic were coated with dust from the Midwest. Some people developed “dust pneumonia” from inhaling the dust. In May 1934, a two-mile-high dust storm blotted out the Statue of Liberty and the U.S. Capitol. On “Black Sunday” in 1935, three million tons of dust blew off the Oklahoma Panhandle and headed east. 250,000 Oklahomans moved to California in five years following the Black Sunday dust storm.

The Federal government established several conservation programs to mitigate the loss of farmland and bring scientific management to bear on uniquely American agricultural challenges. After World War II, congress encouraged development of the nation’s “inland waterways” including the McClellan-Kerr Arkansas River Navigation system (MKARN). If you look at average rainfall in eastern Oklahoma prior to construction of the thousands of acres of impoundment, you will find that after MKARN was built, rainfall actually increased leading to what we now call “Green Country” instead of its former dustbowl status. We changed the local climate a second time.

There are several points worth reiterating here

  • Ignore science at your peril
  • Humans really can change climate (usually it’s not an improvement)
  • People migrate as a result of climate change (it’s happening now)
  • We are only eight inches of topsoil away from extinction

[1] The Homestead Act (1862), Kinkaid Act (1904), Enlarged Homestead Act (1909)

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