The most widespread drought in the U.S. since 1988 has prompted the U.S. Department of Agriculture (USDA) to issue a natural disaster declaration for about 1,000 counties in 26 states, making farm operators eligible for low interest emergency loans. As of July 10, about 78 percent of the corn-growing region in the U.S. were experiencing some form of drought, and drought conditions have intensified in many corn-growing regions during the past several weeks. Bloomberg News characterized the natural disaster declaration as the largest such declaration in the USDA's history.
In a move that reflects the “expected impacts of persistent and extreme June and early-July dryness and heat across the central and eastern Corn Belt,” the USDA’s World Agricultural Outlook Board cut the estimate for the 2012 U.S. corn crop by 1.82 billion bushels on July 11, which is a 12 percent cut. As recently as this spring, farmers were looking forward to one of the largest corn crops in years, thanks to a mild winter and ample precipitation.
Map showing the extent of the drought affecting corn-growing areas of the U.S. Click on the image for a larger version. Credit: USDA.
The disaster declaration covers counties in states from California to Delaware, although it does not include Iowa, the country's biggest corn-producing state. The drought conditions in the U.S. are unusually widespread, although most areas are not experiencing “extreme” or “exceptional” drought conditions, according to the July 10 U.S. Drought Monitor. There have been many more severe droughts in U.S. history, including in the Dust Bowl era of the 1930s.
A key contributor to the drought has been the recent heat that baked much of the country in June and early July, as well as a highly unusual heat wave in March. This week, the National Oceanic and Atmospheric Administration (NOAA) announced that the U.S. has had its warmest year-to-date and warmest 12-month period on record. More than 170 all-time high temperature records were set or tied across the country during June.
“The recent heat and dryness is catching up with us on a national scale,” said Michael J. Hayes, director of the National Drought Mitigation Center at the University of Nebraska at Lincoln, in a press release. “Now, we have a larger section of the country in these lesser categories of drought than we’ve previously experienced in the history of the Drought Monitor.”
Climate studies have shown that the odds of precipitation extremes, including both heavy precipitation and drought, are increasing worldwide as global warming boosts the amount of moisture in the air. However, attributing droughts at the national or regional level is difficult, since natural climate variability plays a large role in influencing weather patterns at such scales. One study released on Tuesday found that manmade global warming made the 2011 Texas heat and drought 20 times more likely to occur compared to the 1960s.
The warm June followed the warmest spring on record, which was the culmination of the warmest March, third-warmest April, and second-warmest May. This marks the first time that all three months during the spring season ranked among the 10 warmest, since records began in 1895.