A new study conducted by climate scientists at NASA’s Goddard Institute for Space Studies revealed that the Dust Bowl of 1930s was the worst drought in over 1,000 years. It was the driest and most widespread drought of the last millennium in North America. Benjamin Cook, co-author of the study, said the Dust Bowl stands out in terms of intensity and extent.
Dust Bowl was 30% more severe than the second worse drought
The drought, which began in 1934, got its name from dust storms that blew dust from the U.S. Great Plains to as far as Florida. It also worked to discourage rainfall. Findings of the study appeared in the journal Geophysical Research Letters. To conduct the study, Cook and his colleagues teamed up with the Lamont-Doherty Earth Observatory.
They used a 2005-year climate record derived from tree-ring chronologies, and the North American Drought Atlas. They found that the Dust Bowl of 1934 covered over 71% of western North America. It was 30% more intense than the 1580 one, the second most severe drought in the last 1,000 years in North America. Scientists also tried to figure out causes of the Dust Bowl.
Two reasons that caused the Dust Bowl
Previous studies have blamed the sea surface temperatures for the Dust Bowl. They said ocean temperatures were marginally warmer in the Atlantic and cooler in the Pacific. However, Cook and his colleagues said that 1934 drought was caused by two reasons. One, a high-pressure ridge over the West Coast during the fall and winter of 1933-34 blocked wet weather from the Northwest and California.
Scientists found that similar ridges preceded many other dry spells on the west coast, including the 1976 California drought. The latest drought in California was also preceded by a similar ridge. The second reason was poor land use practices and agriculture management. They kicked up dust and spread it across the eastern and Midwestern U.S. during the Dust Bowl. Airborne dust particles blocked the Sun’s energy, reduced evaporation and cloud formation.
That means the worst drought in America’s history was aggravated by human activity.