Post by Donald Worster
On October 19 the American media excitedly reported “a massive dust storm” blanketing northern Oklahoma and southern Kansas. For several hours the winds blew dirt eastward from the plains, limiting visibility on the ground to a mere ten feet. The storm turned Interstate 35, which runs from Kansas City to Oklahoma City, into a nightmare. Automobiles collided with one another in the thick fog of dust, and more than a dozen people were injured.
Compared to the devastation wrought by Hurricane Sandy along the heavily urbanized East Coast, this single dust storm may seem a minor event. But people are rightly afraid that this dust event is a harbinger of large-scale wind erosion, of long-term desiccation. We may be facing a return to 1930s conditions, when the plains of North America became a world-class disaster zone, giving a name to modern catastrophes known as “dust bowls.”
Now, as then, local experts often explain the blowing dust as a consequence of “drought.” They point out that the plains have been in a severe drought cycle for several years and that this past summer was unusually bad. Not since the 1930s has the region experienced such a severe shortfall in precipitation. Meteorologists blame the drought on oscillations in the jet stream that have decreased winter snow storms over the United States—and with less snow evaporating, there is less rainfall in the warmer seasons. In other words, all this is out of human control.
But this simple explanation ignores the modern history of the plains and the role of agriculturalists in creating the original Dust Bowl. Drought is necessary for dust storms. Long, severe droughts will devastate all life and overwhelm the croplands and ecosystems alike and overcome their resilience. A big decrease in winter snowfall and spring rain can, if prolonged over years, kill native grasslands and leave the topsoil free to blow. But short of this extreme, what humans allow to grow in the soil makes a big difference. Today, and in fact since the early twentieth century, humans have allowed only their crops to grow over a large portion of the plains. The impact of this human intervention has been to tip the delicately balanced plains ecology toward severe land degradation and instability.
Scientists have worried about this vulnerability for many decades now. At the time of the first big Dust Bowl in the “dirty thirties,” the Nebraska botanist John Weaver (1884–1956) demonstrated a huge difference in the drought resistance of native grasslands compared to human croplands, whether those crops were wheat or corn. Since then, agroecologists at the Land Institute in Salina, Kansas have made the case even stronger. To help us visualize the difference, they have planted indigenous wild grass seed from all the subsections of the prairies and plains and raised them in long plastic tubes. They have done the same with the major food crops. Take both the wild and domesticated plants out of their tubes and you can see what the eye normally does not see: how huge the underground growth of any native grass is, and how puny the roots of domesticated food crops really are. What one sees above ground is only a fraction of the whole. Over millions of years the native grasses have evolved deep root systems that spread underground like a vast net, capturing moisture and anchoring plants against the wind. In contrast, wheat or other cereals artificially selected by humans for food production typically have very small root systems. Mainly this is because they are annuals, not perennials, and therefore put all their energy into producing lots of seeds for propagation. This trait makes them ideal for food production, but it leaves them vulnerable to drought and wind.
If farmers destroy the grasslands and plant wheat in their place, they can raise a food commodity and sell it to those who make flour and breadstuffs. There is little profit in preserving the native grasslands. But in that quest for gain they also leave themselves open to the recurrent droughts that for a very long time have been part of the Great Plains environment. The trade-off is simple and stark. Harvest big crops and make big money in bumper years; watch the crops shrivel and the soil blow away in other years. And watch the whole farming community lurch back and forth between success and failure.
Weather reports leave out this more complicated ecology and history when they simply blame “drought” as the cause of massive wind erosion. But now a new complication enters the picture. To what extent is the current drought in North America due not to the conventional meteorological causes of the past, but to the new threat of global climate change? Climate models predict that, as carbon increases in the atmosphere, droughts will become more frequent and more severe in the western part of North America, along with other parts of the world.
Is the latest Oklahoma dust storm just a freakish act of nature? Most likely it is not. It is probably one more piece of evidence that humans are intervening drastically in earth systems, often with dangerous consequences. What is not known is which of many human interventions created this recent dust storm. Are we seeing the return to the 1930s, or are we facing something even more serious and permanent? How vulnerable is the American food system? Also unknown is exactly what people will do when they see the facts; or whether they will deny them as they have done before.
Donald Worster is a professor emertius of U.S. history at the University of Kansas. Among his publications is Dust Bowl: The Southern Plains in the 1930s. He was a Carson Fellow at the RCC, and is now a distinguished foreign expert and honorary director of the Center for Ecological History, Renmin University of China.