Washington, Oct 15 (IANS): The 1934 drought was by far the most intense and far-reaching in the last 1,000 years in North America, found a research.

The decade-spanning drought that began in 1934 would come to be known as the Dust Bowl and was one of the worst environmental disasters in the history of the United States.

The drought, which affected nearly 72 percent of the western United States, was likely to have been made even worse by atmospheric effects from man-made dust storms.

"We noticed that 1934 really stuck out as not only the worst drought but far outside the normal range of what we see in records," said lead author Benjamin Cook, environmental scientist at NASA's Goddard Institute for Space Studies.

The drought was caused in part by an atmospheric phenomenon that may have also led to the current drought in California, the findings showed.

The three-year drought currently crippling California will cost the state $2.2 billion (Rs. 13,500 crore) in 2014 alone, and is likely to continue through 2015.

The extent of the 1934 drought was approximately seven times larger than droughts of comparable intensity that struck North America between 1000 A.D. and 2005, and nearly 30 percent worse than the next most severe drought that struck the continent in 1580.

The new study used the North American Drought Atlas, a database of drought reconstructions dating back nearly 2,000 years that are based on tree-ring studies.

It also analysed records of air and sea surface temperatures and precipitation to show that the 1934 drought was the worst drought since 1000 A.D.

The study is forthcoming in Geophysical Research Letters.