National Drought Mitigation Center


Collaborative project builds on the GCDI to integrate and map social risk with drought vulnerability

May 16, 2024

This image shows the global Standardized Precipitation Index for December 2023.

By Emily Case-Buskirk, NDMC Communications Specialist

While representing only 15% of natural disasters, droughts took the largest toll on human life from 1970 to 2019 at about 650,000 deaths. That’s according to a 2022 report by the United Nations Convention to Combat Desertification (UNCCD).

To increase resilience to drought and related issues, the second phase of a collaborative project between the National Drought Mitigation Center and the Numerical Weather Modeling Program within the Air Force Weather (AFW) is honing in on the relationship between drought and social risk.

“Building a Global Composite Drought Indicator (GCDI) Hot Spot Early Warning and Information System” is led by NDMC director Mark Svoboda and started in March 2022. For Phase II of this project, the Air Force is providing funding over a 2-year period, ending May 2025.

The effort has expanded to involve collaborators from NASA, the Climate Hazards Center (CHC) at the University of California, Santa Barbara (UCSB) and the University of Nebraska Medical Center (UNMC). This includes:

  • Chris Funk, CHC director, UCSB
  • Greg Husak, CHC principal investigator, UCSB
  • Christopher Hain, research physical scientist and Water Resources Application Areas associate program manager, NASA
  • Sujay Kumar, research physical scientist, NASA
  • Jesse Bell, Claire M. Hubbard Professor of Water, Climate and Health, UNMC

The Phase I GCDI, which produces a new map every month, combines measurements of water availability including precipitation, soil moisture, evapotranspiration and vegetation health to determine potential food security issues.

Partners continuing from the first phase include UNL’s Ross Miller, Department of Political Science; Tirthankar Roy, College of Engineering; and Brian Wardlow, director of the Center for Advanced Land Management Information Technologies (CALMIT).

Adding new dimensions to the GCDI

Moving forward, the second phase will build on the GCDI to integrate and map risk and vulnerability. By leveraging the U.S. Drought Monitor’s hybrid multi-indicator approach, the group hopes to address the novel topic of combining drought with social risk to help Department of Defense decision-makers, Svoboda said.

“The first phase was environmental,” Svoboda said. “Now we’re including social resilience indicators, and sub-seasonal to seasonal climate drought outlooks.”

Goals for Phase II include enhancing the GCDI with machine learning, developing new composite drought indicators, integrating new inputs and incorporating a health component. Each partner will bring different perspectives, tools and skills to address each aspect of the multifaceted objectives.

The CHC is contributing the Standardized Precipitation Evapotranspiration Index to the project. This index builds on the CHC Early Estimates rainfall monitoring product, which is based on data from the Climate Hazards Center InfraRed Precipitation with Stations (CHIRPS).

“Early Estimates of precipitation will be used in tandem with reference evapotranspiration fields, a measure of the atmosphere’s evaporative demand,” Funk said. This provides rainfall supply from precipitation along with water demand from the atmosphere, which can be combined to estimate the Standardized Precipitation Evapotranspiration Index.

Assisting with this effort are affiliated scientists working from different regions of Africa. As full-time CHC employees, they provide on-the-ground information in the Sahel, eastern and southern regions of Africa, in addition to providing station data resources. In turn, the CHC produces datasets and tools to support their drought early warning efforts.

This rainfall data is important because the CHC has observed more intense drought and flood events across the sub-Saharan Africa region, he said, along with expanding populations and warming atmospheres.

“Those all combine to increase exposure, vulnerability and climate shocks — so it’s becoming more and more important to monitor and anticipate,” Funk said.

Within NASA, two centers are working together for this project: the Hydrological Sciences Laboratory (HSL) at NASA’s Goddard Space Flight Center and the Short-term Prediction Research and Transition (SPoRT) center at NASA’s Marshall Space Flight Center.

In the Goddard team, Kumar is working on employing the NASA Land Information System (LIS), a software that enables modeling and data assimilation, to develop a Global Hydrological Intelligence (GHI) framework currently being developed for the GCDI.

“The (LIS) environment is used for research and application support at several agencies, including its primary application in drought monitoring,” he said.

Working in conjunction with this research is SPoRT, which repurposes NASA tools for real-world applications, especially for decision makers.

“We think of SPoRT as an experimental testbed,” Hain said. “We really focus on research to operations, operational research and research to applications.”

Previously, HSL developed the Global Land Data Assimilation System (GLDAS) and the Famine Early Warning Systems Network (FEWS NET) Land Data Assimilation System (FLDAS). These systems are customized versions of the LIS.

Through GHI and other custom configurations, NASA teams can assist the monitoring and forecast requirements related to food security in developing countries.

The UNMC is diving deeper into the intersections between drought and health, a growing area of research. Bell, who led a national assessment on climate and health published in 2016, said there’s still work to be done in defining the connections between climate impacts and human health.

“When you look at the number of ways climate impacts health in the U.S., drought really doesn’t come up,” Bell said. “When you look at fatalities or mortalities, drought isn’t even categorized.”

According to the Centers for Disease Control and Prevention, the climate effects on health encompass eight categories that do not include drought. Bell seeks to change that perception because his research has found profound effects on society due to drought.

“(Drought) costs the U.S. billions of dollars of economic loss and it changes the environment in different ways,” he said. “That’s where I really became interested in understanding that linkage better. With it being slower evolving than other natural disasters, you mostly get indirect or delayed human health outcomes.”

Bell hopes phase II of this project will expound on these possible effects, which could go beyond famine and malnutrition.

“I’m interested in opening pathways to other health outcomes and showing those other relationships, whether it’s heat-related illness, outbreaks of disease, water quality (and) water security … to understand there’s much broader impacts here,” he said.


Worldwide relevance

Africa is not the only continent experiencing water availability issues and other drought-related impacts. In 2022, more than 2.3 billion people faced water stresses, with the number and duration of droughts increasing 29% since 2000, according to the UNCCD “Drought in Numbers 2022” report.

“Through the project, researchers are hoping to prevent conflict stemming from climate-driven migration before it starts,” Svoboda said.

“The longer a drought goes, it’s a cumulative effect — not just on food and water, but health and sanitation,” he said. “The biggest issue for longer-term droughts is that it raises the potential for migration and that causes conflict.”

“By mitigating population displacement, the project has the potential to ultimately improve human health and reduce economic impacts,” Bell said.

“I’m hopeful that this and other projects like this give people a better perspective on how drought leads to human health outcomes,” he said. “There are more opportunities to reduce (negative) human health outcomes and save lives.”


Works Cited

Centers for Disease Control and Prevention. “Climate Effects on Health.” CDC Climate and Health, Accessed 5 October 2023.

United Nations Convention to Combat Desertification. “Drought in numbers 2022 - Restoration for readiness and resilience.” Reliefweb,,of%20roughly%20USD%20124%20billion Accessed 5 October 2023.

U.S. Global Change Research Program. “The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment.”,, Accessed 5 October 2023.