Droughts are ravaging ranches from Australia to Texas, above.

Some of the most iconic images of the Great Depression come from the parched states of the American prairie, where arid land forced farm families to flee in search of jobs and sustenance. Their plight gave rise to Woody Guthrie’s Dust Bowl ballads and John Steinbeck’s“Grapes of Wrath.”

The Dust Bowl was not really a symptom of the Depression. It was brought on by destructive farming practices compounded by years of drought. But its devastating effects worsened the damage of the broader economic collapse.

Something similar is happening around the world now. Persistent droughts from Australia to Afghanistan to Spain to Argentina are combining with the global recession to squeeze farmers and ranchers.

In Northern China, as Michael Wines reported in The Times, the worst drought in half a century is crippling a region that grows three-fifths of the country’s crops. Zheng Songxian, a wheat farmer in the village of Qiaobei, told Mr.Wines he expected to lose at least a third of his crop this year.

“If we don’t get rain before May, I won’t be able to harvest anything,”he added. (Chinese officials have said the drought will not have a noticeable impact on overall grain production.)

The Western United States, from Texas to California, is also contending with a serious water shortage. In California’s heavily agricultural Central Valley, cities like Mendota have seen unemployment rates as high as 35 percent.“My community is dying on the vine,”Robert Silva, the mayor of Mendota, told Jesse McKinley of The Times.

In the Southern Hemisphere, the worst drought in generations is wreaking havoc in Argentina, Uruguay, Paraguay and parts of southern Brazil. Argentine ranchers have lost an estimated 1.5 million head of cattle, Ernesto Ambrosetti, the chief economist at the Institute of Economic Studies at the Argentine Rural Society, told Alexei Barrionuevo of The Times.

There is no clear evidence linking the conditions to climate change. Nevertheless, many scientists are warning that more frequent droughts will be a likely consequence of a warming planet.

To contend with that possibility, researchers are trying to develop crops that can flourish with little water, Andrew Pollack said in The Times. Monsanto, the crop biotechnology producer, said last fall that its first strains of drought-tolerant corn would be on the market within four years, potentially boosting output in dry areas by 10 percent. Because it relies on genetic modification, Monsanto’s work is encountering controversy.

Some Monsanto critics, like the Alliance for a Green Revolution in Africa, say drought resistance can be strengthened through conventional seed breeding.

But in some places, the favored approach to an old-fashioned problem like drought is an old-fashioned solution. As Mr.McKinley reported in The Times, some Californians still rely on dowsers - specialists also known as“water witches,”who use a Y-shaped tree branch and what they say is an intuitive ability to detect water underground.

Frank Assali, an almond farmer in Waterford, California, hired a dowser named Phil Stine.“Phil finds the water,”Mr.Assali told Mr.McKinley.“No doubt about it.”

For those with the knack, work should