March 23, 2009 -- It was one of the worst natural disasters in American History. The fertile Great Plains were blighted by a decade-long drought in the 1930's that brought massive crop failures, dust storms and misery to the country's heartland. But the Dust Bowl was more than just a cruel twist of nature; a new study has found that humans were partly to blame, too. Largely unregulated farming practices left croplands vulnerable to degradation, and the combination of widespread plant death and soil erosion exacerbated already severe drought conditions. Drought in North America is controlled by temperatures in the tropical Pacific Ocean, for the most part. When surface waters are cool, a so-called La Nina event, precipitation usually slackens over the central part of the continent. It's a regular cycle in Earth's climate that repeats every few decades, including the 1950's, and again around the beginning of the 21st century. So what made the Dust Bowl different? Related Content:
"The droughts in the 1950's and 1998-2004 were in many ways just as bad," Benjamin Cook of Columbia University, lead author on the study, said. "But there was less dust available, because strong regulations were put in place after the 1930's to prevent land degradation." Farmers in the 1930's stripped the plains of tough, native grasses, and replaced them with far more fragile crops, like corn and wheat. Moisture from the plants is critical to moderating air temperatures in the region, and when they failed, Cook and his team show that air temperatures spiked by as much as 0.5 degrees Centigrade (0.9 degrees Fahrenheit). Dead crops also meant huge tracts of loose, dry soil that were easily scoured by wind. As dust kicked up into the atmosphere it blocked sunlight and disrupted air circulation in the region, which led to a further decrease in precipitation of between 15 and 2 percent. The team's work appeared last week in the journal Proceedings of the National Academy of Sciences. Get More NewsSpiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates.Oldest Hebrew Writing Possibly FoundAncient inscriptions on a 3,000-year-old pottery shard could make history.Rare, Prehistoric-Age Reptile Found in N.Z.A tuatara has been spotted on the New Zealand mainland for the first time in 200 years.Iceman Has No Living RelativesOetzi, the 5,300 year-old frozen mummy, left no living genetic legacy.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.It's Official: People Are Warming the PolesHumans are conclusively to blame for polar warming, say scientists.Eight-Armed Animal Preceded DinosaursWhat may be one of Earth's first animals was no bigger than a coaster and had eight arms.Phoenicians Live on in People's GenesOne in 17 Mediterranean men may be descended from ancient Phoenicians.Pesticides, Fertilizers Linked to Frog DeclineA pesticide is found to promote parasites among amphibians.Hubble Telescope Taking Photos AgainThe Hubble Space Telescope is once again snapping stunning photos of the universe.Andean Mummy Hairs Show Hallucinogen UseScientists find direct evidence of hallucinogenic drug use among ancient Andeans.Opals on Mars Reveal Planet's Long Wet PastOpals found on Mars suggest the planet has been wet for much longer. |
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