The Dust Bowl and Aftermath
Degraded land, stripped of its vegetation, trodden by the
hooves of cattle or goats, overturned by the plow, turns to dust and
blows away, creating local and global problems. Today, vast regions of
Mongolia are blowing away, creating dust storms that blanket Beijing,
cross the Pacific, and drop dust on North America. In the 1930s, the
dust bowl of North America destroyed farmland, triggered a mass migration
out of the great plains, and led to new farming practices. Even now,much
of the great plains remains vulnerable to desertification. Sand dunes
cover most of Nebraska, held in place by thin layer of vegetation. The
Texas panhandle has many seasonal lakes, playas, that can be easily eroded
The dust bowl was the result of changing weather patterns bringing
drought to a region susceptible to wind erosion and denuded of vegetation
by changes in land use. Let's look at the conditions leading to the dust bowl.
The great plains of North America are the western part of the
great Interior Plains, the wide expanse of flat land stretching from the Mississippi
River to the Rocky Mountains and from the Gulf of Mexico to northern Canada.
Map of the Great Plains.
Geological Story of the Great Plains, by Donald E. Trimble, USGS
Just below the surface of large areas of the Great Plains
are wind-deposited sand and stabilized sand dunes that
can return be easily eroded by the wind when vegetation covering the dunes
The climate of the Great Plains is characterized by:
- Little rain. Rainfall varies from 28 inches per year (700 mm/yr)
in the east to 10 inches per year (400 mm/yr) in the west. Areas with
rainfall less than
28 inches (700 mm/yr) are generally classified as semi-arid. Areas
with rainfall less than 15 inches (350 mm/yr) are generally classified
as arid. The map below shows the Great Plains outline superposed on the
map of rainfall.
- Few rivers.
- High winds. The Great Planes are one of the windiest regions of the
- Cold winters with
snow and blizzard conditions.
- Very hot
summers with thunderstorms, hail, and tornados. The greatest concentration
of tornados is in the Great Plains. Hot summers dry out the land, leading
to wind erosion of areas without vegetation.
- Recurring droughts tied to changes in sea-surface temperature over
large oceanic areas. Farmers are lured into dry areas during
wet years, then they are unable to farm during the drought
years that invariably follow the good years.
The arid and semi-arid plains are poorly suited for agriculture, especially
the types of agriculture practiced by the first immigrants to the region.
We learned in the chapter on The
Oceanic Influence on North American Drought that the oceans strongly
influence rainfall over North America. Schubert et al used this information
to reconstruct the influence of sea-surface temperature on weather
patterns over North America during the major drought of the 1930s.
They found that sea-surface temperature in the tropics was very important.
During the 1930s, the United
States experienced one of the most devastating droughts of the past
century. The drought affected almost two-thirds of the country and
parts of Mexico and Canada and was infamous for the numerous dust
storms that occurred in the southern Great Plains. In this study,
we present model results that indicate that the drought was caused
by anomalous tropical sea surface temperatures during that decade
and that interactions between the atmosphere and the land surface
increased its severity. We also contrast the 1930s drought with other
North American droughts of the 20th century.
the cause of the 1930's Dust Bowl, a Science article by Schubert
et al (2004).
Observed precipitation in the great plains
region of North America 30ªN to 50ªN, 95ªW to 105ªW
(boxed area on maps) compared with precipitation calculated from an
atmospheric general circulation model forced by observed sea-surface
temperature data. The calculated precipitation has been smoothed to
remove fluctuations with periods shorter than six years. The thin black
lines are 14 different simulations. The variation shows some of the
uncertainty of the calculated precipitation. The green line is the
average of the 14 simulations. The maps show the anomaly of precipitation
averaged from 1932 to 1938. Click on the image for a zoom.
From Schubert et al (2004).
Changes in Land Use
Originally the great plains were grasslands divided into
short grass prairies in the west and long grass prairies in
the east. The grasslands supported vast herds of large animals, including
camels, horses, mammoths, bison, giant bison, giant beavers the size
of black bears, and saber-toothed tigers. Most disappeared with the arrival
of humans around 11,000 BC, leaving primarily large herds of bison. (Spaniards
reintroduced the horses used by American Indians). Periodic droughts
and fires kept the plains as grasslands. And the grass had a thick tangle
of roots reaching deep underground to supply water in dry times, and
resources to regrow after fire.
Beginning around 1840, the influx of Europeans into the
Great American Desert as the Great Plains were then known, and new
technology brought rapid change. Cattle barons, moving out of Texas
after the Civil War, soon controlled vast herds of cattle that grew in
size from 1 million in 1870 to 8 million in 1886 (Thomas et al 1997).
At the same time, buffalo hunters killed most of the bison, pushing them
close to extinction. Railroads pushing west after 1866 enabled cattle
to be brought to market from new cities as Wichita, Kansas and Abilene,
Texas. Ranching led to overgrazing in some areas, and the drought of
low prices for cattle, the invention of barbed wire in 1874 and the fencing
of rangeland, and the blizzards of 1885–1886 led to the collapse
of the cattle industry by 1890.
Cattle ranchers were replaced by farmers of European descent,
leading to a rapid increase in population of the plains. Farmers were
drawn to the region by a variety of factors:
- The steel plow, invented by John Deere in 1846, was capable of breaking
the thick sod of the tall-grass prairies.
- The invention of the windmill gave
- The introduction of the mechanical tractor and combine
in the early 20th
century allowed farmers to operate large farms of many acres.
- The introduction of winter wheat from Russia, a variety well adapted
to conditions on the plains.
- The Homestead Act of 1862, designed to speed up the settlement of
the west, gave 160 acres to settlers who would work the land for five
- Very high wheat prices during World War I further fueled the rapid
expansion of farmland, followed by yet more expansion in the
- Railroads and speculators published brochures touting the rich farmland
waiting to be opened up, and offered one-way tickets to farmers willing
to homestead on the new free lands on the plains. By 1890 six million
people had arrived (Thomas et al 1997). Many were tenant farmers working
for large landowners.
Price of wheat in US dollars, adjusted
for inflation. The spike in 1918 was due to demand for wheat
during WW–I, the drop in 1933 was due to the Hawley-Smoot Tariff
Act, the peak in 1944 was again due to world war, and the peak in 1974
was due to large imports by the Soviet Union. The overall downward
trend since 1940 is due to more efficient farming practices, new strains
of wheat, and irrigation. Note: These prices are approximate.
There were many markets selling wheat at different prices, and the
influence of inflation was different for different crops and goods.
See the Historical Statistics site for more information.
From Historical Statistics of The United
spring wheat, and winter wheat–acreage, production,
price, and stocks: 1866–1999.
The new farmers raised crops using methods suitable for
Europe and the eastern United States, but these farming methods led to
disaster on the Great Plains. They plowed deeply to eliminate weeds and
crops, harvested the crops, and left their fields bare until the next growing
season, although frequent plowing reduced soil moisture, broke up clods,
and produced a layer of dust at the surface, all of which facilitated
wind erosion. They tended to raise wheat because Russian wheat grew well,
it brought high prices, and it was easy to grow and harvest using mechanical
Collapse of Farming and the Dust Bowl
The widespread plowing of the plains beginning in the early 20th
century destroyed the original short-grass prairie, replacing it with wheat
fields.The collapse of wheat prices after World War I pushed farmers
to further expand acreage devoted to wheat in a futile attempt to raise their
income. Then the Hawley–Smoot
Act Tariff Act of 1930 was passed by Congress
in a disastrous attempt to stem the financial crisis of 1929 by reducing the
import of foreign goods and crops. This led to retaliatory tariffs which greatly
reduced the export of American wheat, driving wheat prices to historic lows
and forcing farmers throughout the Great Plains into bankruptcy. Prices fell
from $70/ton during World War I to $35/ton in 1929 to $7/ton in 1931 (Thomas
et al 1997).
When drought began in the early 1930s, the wheat failed to sprout,
leaving bare, plowed fields at the mercy of the strong winds sweeping across
the plains. Vast dust storms followed, destroying farms and driving 50,000
people a month from the land at the height of the Dust Bowl.More than 300,000
rural people left the plains for California. Their story was told eloquently
by John Steinbeck in Grapes
of Wrath published in 1939.
Grapes of Wrath book cover.
From Syracuse Library Special
Collections Research Center Exhibition on Steinbeck's
Grapes of Wrath: Bitter Fruit of the Great Depression.
Buried machinery in barn lot in Dallas, South Dakota, United States
on 13 May 1936 during the Dust Bowl. Click
on the image for a zoom.
From United States Department of Agriculture; Image Number: 00di0971from
25 million hectares of land were eroded by the wind by
1936. Some topsoil was deposited as far as Washington DC and 2000 kilometers
out over the north Atlantic (Thomas).
The dust bowl led to the establishment of the Soil Conservation
Service that drew on engineers, agronomists, and range management experts
to develop best farming practices for the Great Plains. They recommended
Resources Conservation Service: Conserving the Plains: The Soil Conservation
Service in the Great Plains):
- Use of contour plowing, strip cropping, erosion control dams, and
other measures to reduce runoff of rain and increase the retention
Strip crops and contour plowing reduce soil erosion and rapid runoff
of rain water.
From Oregon State University. New
concepts could change face of America's cornbelt.
- Use of strips of vegetation and trees to slow the wind,
- Leave crop residues on the surface, and use stubble mulching
and minimal tillage to reduce erosion,
Stubble mulching to reduce soil erosion.
- Conversion of
the most easily eroded land from farming to ranching based on good
- Eliminate overgrazing, rotate cattle through pastures, apply ecological
concepts to range management,
- Use federal subsidies, crop insurance programs, and allotments to
discourage farming unsuitable drylands.
Initially, farmers employed these soil conservation measures.
But above normal rainfall in the 1940s and record high wheat prices during
World War II led to the expansion of wheat farming into unsuitable area, and
soil conservation methods were abandoned. Drought returned to the great plains
causing further damage, dust storms, and soil erosion. In 1956, in an effort
to reduce future damage, the US Department of Agriculture began the Soil
Bank Program that paid farmers to remove marginal drylands from cultivation.
Some lands were planted in trees. In 1956, soon after the program started,
500,000 farmers agreed to take 10,720,749 acres out of production. By
1960, 28.7 million
acres were in the soil bank.
The results of good (and poor) soil conservation practices
are readily seen today in many parts of the Great Plains.
Grassland management needs to involve grazing.
Fall scene of season-long grazing at the end of one of the driest years
on record in the Sandhills of Nebraska. Plants will be in an extreme
weakened condition to begin plant growth next spring.
Sandhills' Greatest Resource.
Pasture scene from the Sandhills of Nebraska
taken in the late summer of one of the driest years on record. The
grassland is part of a large herd, short duration system.
Sandhills' Greatest Resource.
Great droughts may return to the Great Plains if earth
warms due to increasing levels of carbon dioxide in the atmosphere and
we return to the warmer climate of the medieval warm period.
The western United States is experiencing a
severe multiyear drought that is unprecedented in some hydroclimatic
records. Using gridded drought reconstructions that cover most of the
western United States over the past 1200 years, we show that this drought
pales in comparison to an earlier period of elevated aridity and epic
drought in AD 900 to 1300, an interval broadly consistent with the Medieval
Warm Period. If elevated aridity in the western United States is a natural
response to climate warming, then any trend toward warmer temperatures
in the future could lead to a serious long-term increase in aridity over
western North America.
Aridity Changes in the Western United States by Cook
et al (2004).
Dust Storms In Central Asia
Spring dust storms have become common in China, increasing from
one in three years in the 1940s to 18 in 2001. The sand storms originate in
the arid areas of southern Mongolia and northern China, and they carry dust
across eastern China, Japan, the Pacific, and North America. In May 2007, dust
from one storm was tracked as it circled the earth three times before dissipating.
They result from land degradation due to over grazing in the arid areas. Today's
conditions in Mongolia are reminiscent of conditions leading up to the dust
- Large flat areas underlain by sand and loess deposits easily eroded by
- High winds.
- Little rain. 2 inches/year (50 mm/yr) in the Gobi Desert in the south to
20 inches/year (500 mm/yr) in the north.
- Extreme range of temperature with a 50ªC range in average temperatures
from winter to summer.
- Few rivers. Most precipitation evaporates, 6% runs off, 3% percolates into
- Land degradation.
- The population has tripled since 1960, increasing from 0.9
million in 1960 to 2.8 million in 2005.
- Mongolia changed from a free, nomadic society to a centralized, collective
society in the 1920s. Then changed back to a somewhat free nomadic society
in the 1990s. But the old ways had been mostly forgotten. Too many people
raising too many animals without traditional knowledge of the country's
ecology, and without traditional controls of
herding, led to land degradation. The old traditions of the "commons"
had been lost in the 70 years since the 1920s, leading
to a true "tragedy of the commons" in the 1990s.
In Mongolia, private property in pastureland has never existed, and
privatization of pasture remains unconstitutional. Rather, there existed
a complex of distinct but often
overlapping or nested tenures to a variety of resources vested in groups
of different sizes
and social functions and governed by an array of formal and informal
pastoral resources included seasonal pastures (winter, spring, summer
natural and man-made water sources, campsites, animal shelters and
grounds, salt licks, and stock driveways. Prior to Mongolia’s
communist revolution in
1921, pasture allocation and use were governed in many areas by a combination
formal regulation imposed by ruling nobles (either secular princes
or high-ranking lamas
in the Tibetan Buddhist church), and informal norms and customs described
by herders as “unwritten law.” During the
last thirty years of socialist government (1960-1990), pasture use
was regulated by the state, through the mechanism
of the negdel or collective, although customary patterns of use and
negdel decisions to varying degrees. Since the demise of socialism
in Mongolia (1990),
and the difficult emergence of a market economy and democratic political
pasture use has not been formally controlled. The collectives that
once allocated pastures
and campsites and directed seasonal movement patterns were dismantled
in 1992 and
state-owned livestock were privatized.
- As a result of political changes in the 1990s, native grasslands are
being over grazed and destroyed.
- Demand for agricultural products has led to conversion of pasture to
farmland with spring tilling coinciding with the season of highest
- Drought. Severe droughts have recently become more common after decades
of slightly increasing drought index values since 1940 (Batima et al 2007).
The latest droughts were in 1999–2002
(the worst in 60 years) and 2008 (the driest since 1951 in north China and
Terra satellite captured this image of a dust storm over the Taklimakan
Desert, in western China on April 7, 2004.
Dust Storms on The Rise.
You can learn much more about the great plains at the US
Diplomatic Mission to Germany's web site on the geography
of the western US. Donald Trimble has a good introduction to the
of the great plains.
The American documentary films The
Plow That Broke the Plains and The
River (1936) originally produced by the US Government Resettlement
Administration, describe environmental problems culminating
in the Dust Bowl, and the great floods of the Mississippi River in the
1930s. The films won many prizes and pioneered new filmmaking techniques.
Available on Google
Fernandez-Gimenez, Maria E., and B Batbuyan. 2000. Law and Disorder
in Mongolia: Local Implementation of Mongolia's Land Law. Presented
at "Constituting the Commons: Crafting
Sustainable Commons in the New Millenium", the Eighth Conference
of the International Association for the Study of Common Property, Bloomington,
Indiana, USA, May 31-June 4. Digital
Library of the Commons.
Punsalmaa Batima, Luvsan Natsagdor, and Nyamsurengyn Batnasan. 2007.
Vulnerability of Mongolia's pastoralists to climate extremes and changes.
Change and Vulnerability. Edited by Neil
Leary, Cecelia Conde, Jyoti Kulkarni, Anthony Nyong, Juan Pulhin. Earth
scan Publications Ltd: 68–87.
Schubert, S. D., M. J. Suarez, et al. (2004). On the Cause of
the 1930s Dust Bowl. Science 303 (5665):
During the 1930s, the United States experienced one of the most devastating
droughts of the past century. The drought affected almost two-thirds
of the country and parts of Mexico and Canada and was infamous for the
numerous dust storms that occurred in the southern Great Plains. In this
study, we present model results that indicate that the drought was caused
by anomalous tropical sea surface temperatures during that decade and
that interactions between the atmosphere and the land surface increased
its severity. We also contrast the 1930s drought with other North American
droughts of the 20th century.
Thomas, Squires, and Glenn (1997) The North American Dust
Bowl and Desertification. In: Middleton and Thomas (eds) World
Atlas of Desertification 149–154.
24 July, 2009