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Friday, August 17, 2012

Drought in the United States: Causes and Issues for Congress

Peter Folger
Specialist in Energy and Natural Resources Policy

Betsy A. Cody
Specialist in Natural Resources Policy

Nicole T. Carter
Specialist in Natural Resources Policy

Drought is a natural hazard with potentially significant societal, economic, and environmental consequences. Public policy issues related to drought range from how to identify and measure drought to how best to prepare for, respond to, and mitigate drought impacts, and who should bear associated costs. This report provides information relevant to drought policy discussions by describing the physical causes of drought, drought history in the United States, examples of regional drought conditions, and policy challenges related to drought.

By summer 2012, drought has extended across nearly two-thirds of the United States and has adversely affected agricultural producers. As of mid-July 2012, more than 1,000 counties have been designated as disaster counties by the U.S. Secretary of Agriculture. The designation makes qualified farmers and ranchers eligible for low-interest emergency loans. The 2012 drought is fueling interest in near-term issues, such as current (and recently expired) federal programs and their funding, and long-term issues, such as improving drought forecasting and the mix of drought relief and mitigation actions and federal water project and agency preparedness and role in relief. 

What is drought?
Drought is commonly defined as a lack of precipitation over an extended period, usually a season or more, relative to some long-term average condition. History suggests that severe and extended droughts are inevitable and part of natural climate cycles. While forecast technology and science have improved, regional predictions remain limited to a few months in advance. 

What causes drought?
The physical conditions causing drought in the United States are increasingly understood to be linked to sea surface temperatures (SSTs) in the tropical Pacific Ocean. Studies indicate that cooler-than-average SSTs have been connected to the severe western drought in the first decade of the 21st century, severe droughts of the late 19th century, and precolonial North American “megadroughts.” The 2011 severe drought in Texas is thought to be linked to La NiƱa conditions in the Pacific Ocean. 

What is the future of drought in the United States
? The prospect of extended droughts and more arid baseline conditions in parts of the United States could suggest new challenges to federal programs and water projects, which were conceived or constructed largely on the basis of 20th century climate conditions. Some studies suggest a transitioning of the American West to a more arid climate, possibly resulting from the buildup of greenhouse gases in the atmosphere, raising concerns that the region may become more prone to extreme drought than it was in the 20th century. Some models of future climate conditions also predict greater fluctuations in wet and dry years. 

What is federal drought policy?
Although drought impacts can be significant, no comprehensive national drought policy exists. Developing a national policy would be challenging because of split federal and non-federal responsibilities, the existing patchwork of federal programs, and differences in regional conditions, risks, and available responses. In 2000, the National Drought Policy Commission provided recommendations to Congress on improving drought policy. Congress has acted on some of the recommendations (e.g., authorizing the National Integrated Drought Information System), but not others (e.g., creation of a National Drought Council and a fund to support drought planning). Given current conditions, Congress may review the functioning and adequacy of existing federal responses and programs (e.g., access to and level of assistance provided, incentives for mitigation of drought risk, preparedness of federal facilities).

Date of Report: July 31, 2012
Number of Pages: 32
Order Number: RL34580
Price: $29.95

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