Posted on 04/30/2008 1:01:15 PM PDT by blam
Climate modelers see modern echo in '30s Dust Bowl
April 29, 2008
Goodwell, Oklahoma, June 4, 1937.
Climate scientists using computer models to simulate the 1930s Dust Bowl on the U.S Great Plains have found that dust raised by farmers probably amplified and spread a natural drop in rainfall, turning an ordinary drying cycle into an agricultural collapse. The researcher say the study raises concern that current pressures on farmland from population growth and climate change could worsen current food crises by leading to similar events in other regions.
Recent studies indicate that periodic droughts in the western United States are controlled by naturally occurring periods of cool sea-surface water temperatures over the eastern tropical Pacific—so-called La Niña phases. Via long-distance winds, these phases indirectly affect faraway rain patterns. In addition to the 1930s, such patterns have occurred in the 1850-60s, 1870s, 1890s, 1950s, and 1999 to present.
What made the 1930s different was the arrival of farmers onto the Great Plains, where they replaced drought-resistant wild prairie grasses with fragile wheat, neglected to plant cover crops in unused fields, and allowed livestock to overgraze pastures.
When the 1932-1939 drought struck, plants shriveled and ever more bare soil was exposed. The land was quickly eroded by gigantic dust storms, and farming collapsed. Skies were chronically darkened on and off; in some years, an estimated 770 million metric tons of topsoil were lost, and over the whole time, 3.5 million people were displaced--one of the 20th century’s worst environmental disasters. The new study finds that farm dust probably fed the disaster, doubling the drop in rainfall, and moving the drought itself northward into major farming regions.
The researchers, based at Lamont-Doherty Earth Observatory and NASA Goddard Institute for Space Studies (both affiliates of Columbia University’s Earth Institute) used a computer model to simulate a 1930s drought driven only by the change in sea-surface temperature. This showed a 5% drop in rainfall, centered over northern Mexico and the U.S. southwest, where little agriculture then took place. This would have affected the Great Plains too, but probably would have not brought disaster. Then the modelers added in the effects of dust, using data from the ‘30s that indicated dust sources, and allowing the computer to create dust storms. This yielded a simulated event eerily like the real one, with a full 10% drop in rain—to just 18 inches a year--and centered over the prairie farm regions of north Texas, Oklahoma, Missouri, Kansas, Nebraska and Iowa.
Lead author Benjamin Cook, a National Oceanic and Atmospheric Administration postdoctoral researcher affiliated with both Lamont and Goddard, said the effect occurred because dust particles suspended in air reflect solar radiation. Studies by researchers in other parts of the world show that this causes a drop in temperatures at or near the soil surface, lessening evaporation of moisture into the air, and thus decreasing precipitation even further. Dust on the Great Plains helped draw the drought northward like a siphon, said Cook. “This is what made the Dust Bowl the Dust Bowl,” he said. “It was a process that fed on itself.”
The U.S. southwest is currently suffering a serious long-term drought that threatens agriculture and population growth there. Cook said it is unlikely that this by itself will cause another Dust Bowl in the United States. Among other things, the U.S. Natural Resources Conservation Service, founded in response to the ‘30s crisis, has shifted farmers into more sustainable practices. On the other hand, Cook points out that many scientists believe hard-pressed farmers and herders in China and Africa’s Sahel region may be repeating the experience, ruining marginal lands in order to feed themselves in the short term.
“This highlights the fact that humans can alter natural events and make them worse,” said coauthor Richard Seager, a modeler at Lamont. Seager says that scientists studying global climate change predict many subtropical regions will dry in coming years. “That, in combination with the pressure from rising population and demand for food, could lead to a similar cycle of drought, dust storms and more drought,” he said. “The lesson of the Dust Bowl is there to be learned.”
Citation: “Dust and sea surface temperature forcing of the 1930s ‘Dust Bowl’ drought” appears in the current online edition of Geophysical Research Letters: http://www.agu.org/journals/gl/gl0808/2008GL033486/ .
Source: Columbia University
So what if that means pumping aquifers dry & tilling millions of acres of land, which would otherwise lie fallow. If we're going to prevent a dust bowl, empty aquifers are a small price.
/moonbat envriowhacko emoting mode
Farmers are a lot smarter than they were back in the dustbowl days. They use completely different tillage techniques now and fields are planted and used completely different than back then.
We may have a “dustbowl” drought, but it will be completely different than the pictures we see from then, topsoil is too darn valuable to just let it blow away.
I thought the “Dust Bowl” was caused by The Great Depression (not drought) and by farmers walking away from their fields because they weren’t economically viable. The lack of crops exposed the soil, but it wasn’t a drought that started it.
Am I missing something?
I am getting real sick of these goofballs and their damn computer models....morons
The way the fields are plowed was changed after the Dust Bowl. This is well-known, except at Columbia.
They should have raised corn or wheat instead
“We’re DOOMED!!”
LOL.
No wonder the crops weren’t economically viable.
There is a term that is used when semi-arid climates transition to arid desert climes and that is “desertification.” And many third world countries such as sub-Saharan Africa are having problems due to overgrazing and lack of a responsive government such as in the Sudan.
In this country, where I am located we haven’t had significant precipitation since early December of last year. No winter or spring rains at all. And currently for the next two days we are having blowing dust and sand that is reducing visibility and increasing fire threats as humidity is less than 10%
Clear and Windy
82°F
(28°C)
Humidity: 9 %
Wind Speed: SW 29 G 39 MPH
Barometer: 29.76”
Dewpoint: 18°F (-8°C)
Heat Index: 80°F (27°C)
Visibility: 10.00 mi.
Most telling scene in “Grapes of Wrath”
Little girl at the communal “camp” turns on the water spigot for a drink and leaves it running.
It was supposed to symbolize the plenty such living would provide, but to me it symbolizes the waste by those who don’t have to work for what they receive.
It is not minor, and your conclusion is without any scientfic foundation. The debate within the scientific community is not whether CO2 can affect climate,which is long settle, but rather what is the acceptible level and how many decades do we have before we have to mend our ways.
My mom and dad were on a road trip, and while driving past some farms, my dad saw a bunch of kids spraying stuff in many of the fields. In the next town, he saw a group of farmers in a restaurant. He asked them what that was about (he grew up on a farm in MN). They told him they don’t till the soil anymore. They just hire teenagers to go spray Roundup all over everything, then they plant again when it’s time.
If true, that doesn’t sound like too good an idea to me, though I admittedly know nothing about farming.
Farmers in the region that was the Dust Bowl of the 30’s don’t use a plow any more. The modern movement is “no till,” which is used to preserve litter on top of the soil, keep more moisture and organic matter (which means carbon) in the soil.
The aquifer issue is being taken care of with regulation. Junior water rights holders in the states over the Ogallala aquifer have had their water rights severely restricted for years.
Spraying herbicides is the key to no-till farming. It used to be that farmers used tillage to eliminate weeds (and possibly insects, mites and nematodes in root matter).
Now, with cheap pesticides (and Roundup is a pesticide, a herbicide specifically), it is cheaper to spray than till (especially with diesel at $3.50+/gal).
With Roundup (ie, glyphosate is the generic chemical name), you have an herbicide that kills nearly everything but the GMO corn/soybeans. Roundup has no persistence in the environment; it is de-activated by soil. I’ve sprayed Roundup on a field and you could see where it was deactivated by blowing dust.
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