Urgency of Drought Beginning to Sink In
New System Would Sound Early Warning for Silent Threat
Science Communications Specialist
Institute for Global Environmental Strategies
The typical drought starts innocuously enough. An approaching line of thunderstorms suddenly fizzles. A potential mountain snowstorm fails to materialize. Several weeks later, Mother Nature has quietly settled into a pattern of below-normal precipitation and above-normal temperatures. As weeks turn into months, soil moisture dries up, groundwater levels drop, and plants and animals grow parched. Water — one of our most precious resources — becomes scarce.
The subtlety of drought is probably one reason it fails to receive the attention it deserves. Almost by definition, drought is not a headline-grabber. It is easier to sensationalize too much water — as in the case of flooding or a tsunami — than too little, and compared with the pronounced and often immediately devastating impacts of hurricanes and tornadoes, drought keeps a low profile as it attacks slowly but steadily.
While drought may lack the shock-and-awe quality of other natural disasters, its impacts can be just as far-reaching and costly, if not more so. Regional agriculture, ecosystems and economies can suffer severe consequences that last indefinitely. On average, according to the Na-tional Oceanic and Atmospheric Administration (NOAA), drought costs the U.S. economy an estimated $6 billion to $8 billion per year, more than the average annual losses of $5.1 billion due to hurricanes or $5.2 billion due to floods.
Yet, there is no coordinated federal effort to improve monitoring and prediction of drought. Led by NOAA, the proposed National Inte-grated Drought Information System (NIDIS), now waiting for congressional approval, would integrate in situ and remotely sensed data from various government agencies and organizations into a Web-accessible system that provides users with the information and tools necessary to better prepare for drought and to mitigate its effects.
Supporters say NIDIS represents an important step toward establishing a national drought policy that reduces the social and economic impacts of drought by shifting the focus from after-the-fact response to pre-event planning. The savings could be substantial, according to Donald Wilhite, director of the National Drought Mitigation Center (NDMC) at the University of Nebraska. In a Senate hearing on drought in April, he testified that studies have shown that for every dollar spent on preparing for and mitigating the effects of natural hazards ahead of time, four dollars are saved on response and recovery.
“If we can reduce those (drought) impacts, then we certainly reduce the need for government drought relief efforts, which takes the burden off … the American taxpayer,” Wilhite said. “Investing up front is really the key.”
Communicating the seriousness of drought and the importance of taking a proactive approach has been a challenge for elected officials, including Senator Ben Nelson, D-Neb., who is co-sponsoring a Senate bill that would authorize funding for NIDIS and whose state has experienced ongoing drought since 2000. Conditions there have gotten so bad that in July the U.S. Department of Agriculture (USDA) designated 49 counties as disaster areas.
“One of my biggest frustrations the past few years … has been making people understand that this drought really is a disaster, as much as a hurricane, or an earthquake or a tornado, just of a different kind,” said Nelson in opening remarks at the April hearing. “I even named the drought in Nebraska — Drought David — in an effort to crystallize the drought so that people could see that it’s the same kind of experience, in a different way, as any other natural disaster.”
Nebraska is part of a swath of western states that have suffered from persistent drought during the past several years. As of the end of June, NOAA’s National Climatic Data Center reported that 45 percent of the country was in the midst of moderate to extreme drought. The most severe conditions in July affected Texas, the Northwestern Plains and parts of the Western Gulf Coast. See Figure 1. Making matters even worse was a record-setting heat wave that stretched from coast to coast from mid-July through early August. According to NOAA, it was the country’s second-hottest July, only 0.3 degrees behind July 1936, with more than 2,300 daily temperature records broken.
The blistering heat and unrelenting dryness have destroyed crops, forced ranchers to prematurely sell their cattle and cost the federal gov-ernment billions of dollars in insurance payouts. Reduced rain and snow have also contributed to enhanced wildfires. NOAA estimates the western fire season of spring-summer 2000 resulted in nearly 7 million acres burned and $2 billion in damage. According to statistics kept by the National Interagency Fire Center, the current fire season is on pace to be the worst in this decade, with more than 5.5 million acres having burned as of early August.
The risks posed by drought are especially worrisome in the West, where population growth — four of the five fastest-growing states during 2004 and 2005 were west of the Mississippi — is expected to increase future water demand in an area of the country particularly prone to extended drought. Adding to concerns is the possibility that climate change due to natural and human-induced causes could lead to longer and more severe droughts, further straining already stressed water resources.
Not surprisingly, a group representing the interests of 22 western states and U.S. territories, the Western Governors’ Association (WGA), has been the driving force behind NIDIS and other drought initiatives. In response to the 1995-1996 drought in the Southwest and Southern Plains, blamed for $5 billion in losses in Texas alone, the WGA adopted a drought response plan that eventually led to Congress approving, and President Clinton signing, the National Drought Policy Act of 1998. The act created a commission to draft recommendations for a federal policy that would enable improved preparation for, and response to, drought emergencies.
Since the commission’s report was issued in 2000, however, three bills designed to implement such a policy have failed to reach the House or Senate floors, even as scientists have said the recent drought in the West could be the worst in 500 years. Part of the problem, according to those trying to push drought legislation forward, is convincing lawmakers from other areas of the country — where drought tends to be less frequent and more fleeting — that the issue is a matter worthy of urgent action.
In the Southeast, for example, August 2001-July 2002 ranked as the seventh driest August-July on record. Underground wells were drying up, river and lake levels had dropped well below normal, and there were growing fears that insufficient water for manufacturing plants would force some businesses to shut down. By September 2002, however, the region was already on its way to recovery, having recorded its fourth consecutive month of near- to above-normal rainfall. More recently, an abnormally dry spring earlier this year pushed parts of the Mid-Atlantic to the verge of full-fledged drought, with several states recording their driest March ever, before record rains in late June quickly transformed drought worries into flood concerns.
“Drought regularly affects states outside the West as well, although it is not as frequent or as severe as we see in the West,” said Kevin Moran, director of WGA’s Washington, D.C. office. “WGA, therefore, tries to reach out and build coalitions with stakeholders (outside the West) in sup-port of a more proactive approach to drought. Unfortunately, it’s difficult for many of them to maintain the level of interest needed to get legislation moving in Congress because the rain starts to come down and they move on to other, more immediate problems.”
Unable to move forward the comprehensive drought policy legislation, backers decided this year to separate one of its components, NIDIS, into its own bill. NIDIS would expand and improve upon the quantity and quality of data that go into drought monitoring and forecasts.
Currently, the main mechanism for tracking drought in the United States is the U.S. Drought Monitor, a weekly map that depicts the inten-sity of drought conditions in different locations based on a combination of objective data — precipitation and temperature observations, soil moisture estimates, streamflow rates, groundwater levels, and remotely sensed measurements of vegetation health and snowpack — and on subjective assessments by scientists. See Figure 2 on page 16. Three-month forecasts of large-scale drought trends are issued on a monthly basis via the U.S. Seasonal Drought Outlook, and are based on the subjective synthesis of various forecasting tools. See Figure 3 on page 17.
Neither product, experts say, provides the level of detail or tools necessary to support, far enough in advance of drought, adequate de-cision-making by water managers controlling the flow of water through reservoirs, by farmers deciding what types of crops to plant and when, by forest managers assessing fire risk, and by others involved in water-sensitive activities.
In addition to conventional surface-based indicators of drought, NIDIS would incorporate newly developed remote sensing capabilities. For example, NDMC has worked with the U.S. Geological Survey (USGS) Earth Resources Observation Systems Data Center on a 1-km resolu-tion vegetation dryness index, calculated in part from satellite measurements. See Figures 4 and 5. NDMC is also collaborating on a project with scientists at NASA’s Jet Propulsion Laboratory to develop new soil moisture products based on remotely sensed data.
|Figure 4 VegDRI map for July 25, 2006; VegDri is an experimental drought index developed by USGS in collaboration with the National Drought Mitigation Center. The index is based on a combination of 1-km resolution satellite data from NOAA’s Advanced Very High Resolution Radiometer and other climate and biophysical data. Imagery is courtesy of the U.S. Geological Survey Center for Earth Resources Observation and Science (USGS EROS). |
While access to new and improved data is an important aspect of NIDIS, so is the plan to integrate that data with analysis programs and Geo-graphic Information System software, allowing decision makers to better assess and visualize the risks that an oncoming drought might bring.
The integrated approach to NIDIS parallels that of the Global Earth Observation System of Systems (GEOSS), which recently has served to help NIDIS gain traction. Initiated by the Bush administration in 2003, GEOSS is an international effort to link the world’s widely distributed Earth-observation instruments and the data they collect into a cohesive system, one that promises to aid decision-making in natural resource man-agement, transportation, public health, emergency response and many other sectors.
NIDIS has been identified as a high-priority item to be developed as part of the U.S. Integrated Earth Observation System (IEOS), the U.S. con-tribution to GEOSS. The challenge of predicting drought highlights the underlying theme of GEOSS: that the interconnected nature of Earth’s various components — its land, atmosphere, oceans, plants, animals and human life — requires an integrated approach to gathering data and con-verting it into useful information. A variety of factors goes into determining where drought will form and how long it will last, ranging from rain and snow amounts to the intensity of solar radiation that reaches the ground and evaporates soil moisture.
Like IEOS, the success of NIDIS will depend on cooperation among multiple federal agencies, including the USDA, USGS and NASA, as well as state and local governments and the private sector, to assimilate data collected by instruments scattered around the world and often generated on different time scales and in nonstandard formats. In fact, former Governor of Wyoming Jim Geringer, an active advocate of NIDIS and GEOSS, says that the task of coordinating the efforts of so many different entities rivals the technical challenge of linking the data itself.
“Current technology could integrate the disparate global sources of information that are not effectively connected, but it has not been guided by a national policy that would foster an integrated approach,” said Geringer, now director of Policy and Public Sector Strategies at ESRI, a geospatial solutions company. “Cultures and organizations require integration as well.”
Figure 5 Normalized Difference Vegetation Index (NDVI) data from Aug 10, 1999 shows greener (wetter) than normal conditions, and on the same date in 2002, widespread brown (drought) areas are visible in Colorado and Arizona. This data was measured by the vegetation instrument on France’s SPOT satellite provided by DigitalGlobe/SPOT, under agreement with the U.S. Department of Agriculture Foreign Agricultural Service (USDA/FAS) and provided by NASA/Goddard Space Flight Center, Scientific Visualiza-tion Studio.
NOAA is already involving an array of data providers and users — from state climatologists to city water managers to the academic com-munity — in preliminary work to develop a detailed plan for NIDIS’s implementation, pending congressional approval, including a prototype of the system’s Web portal. While no action on NIDIS is scheduled in the Senate as yet, a companion bill in the House was passed on Sept. 26.
Ironically, NIDIS has built political momentum of late, thanks in part to the same disasters that traditionally have stolen the spotlight from drought. Recent events that have inflicted unprecedented human and financial tolls, including the Indian Ocean Tsunami and the record-setting 2005 hurricane season in the U.S., have helped illustrate the need to stay a step ahead of the environment, rather than behind.
“We cannot afford to continue the policy of reconstruction after destruction,” Geringer said. “The missing ingredient? An integrated system that could better inform us individually and collectively in advance of potentially catastrophic events.” In the case of drought, such a system could sound an early alarm bell on the most silent and creeping of natural threats.