Climate adaptation, Water conservation, Water resources
An Analysis of Drought Exposure, Impacts, and Adaptation in the South-Central U.S.
Case Study by Conservation and Adaptation Resources Toolbox and the Drought Learning Network
Status
Ongoing

Location

States

Arkansas, Louisiana, New Mexico, Oklahoma, Texas

Ecosystem

Desert, Prairie

Subject

Adaptation
Agriculture
Climate change
Drought
Economics
Hydrology
Vulnerability

Introduction

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Drought is one of the most harmful natural disasters on earth. The National Oceanic and Atmospheric Administration’s (NOAA) records from 1996 to 2016 state that drought cost the United States nearly $1.7 billion a year, as drought decreases water supplies, stresses agricultural systems, and challenges energy production (Mihunov et al., 2018; Mihunov et al., 2019; Mihunov and Lam, 2020). Drought not only threatens economic stability, but also exacerbates human physical and mental health concerns. 

Community resilience describes how well human communities respond to and recover from hazards. Community resilience is a result of three interacting elements: a community’s hazard exposure (i.e., stress degree and duration), damage received (e.g., economic loss), and recovery (e.g., population or economic growth following the hazard). Community resilience has been extensively studied for hurricanes, earthquakes, and other relatively predictable, or short-term, natural hazards (Lam et al., 2015; Lam et al., 2016). However, community resilience to drought is largely understudied despite drought’s increasing frequency, extent, and severity.

In response to this research gap, scientists from Louisiana State University partnered to examine drought community resilience in the south-central U.S. The team sought to test the validity of drought characterization tools, measure community resilience, and examine the factors that contribute to resilience scores. 

This information was examined over the 503 counties of Arkansas, Louisiana, New Mexico, Oklahoma, and Texas. This region varies in drought exposure, as well as natural and socioeconomic characteristics. For this reason, this region provides a valuable setting for community resilience comparison. This work aims to improve the understanding and communication of drought impact to bolster preparedness, while revealing underlying factors that explain communities’ readiness to withstand stress. Further, this work advances efforts to create a universally applicable method to assess community resilience to natural hazards, incorporating both natural and social systems.

Key Issues Addressed

Drought can be defined and measured in a multitude of ways based on meteorological, agricultural, hydrological, or socioeconomic effects. Drought indices offer one way to represent drought severity. Because they compile rainfall, snowpack, streamflow, and other water-supply indicators into a single value, drought indices have become the preferred tool for decision-making among resource managers (Rohli et al., 2016; Bushra et al., 2019).

However, index metrics do not provide explicit insight into how diverse and dynamic human communities will be affected by drought. For example, what can drought indices tell us about actual crop or property damage? How might communities be differentially impacted by the same drought? Further, because human communities are not static and drought occurs as a prolonged event, examining impact over time is critical. By bridging the gap between drought metrics and human systems, communities can know how to best fortify and evaluate their resilience to drought.

Project Goals

  • Validating Drought Indices: Linking drought indices to actual damage is critical for improving the communication of drought onset and danger to the public. The Palmer Drought Severity Index and Palmer Hydrologic Drought Index are widely accessible indices that describe drought intensity and duration. The Spatial Hazards Events and Losses Database of the United States captures drought-induced crop and property losses, injuries, and fatalities as monetary amounts. Additionally, NOAA employs six of their polar orbiting satellites to produce the Normalized Differential Vegetation Index (NDVI), a reliable long-term record of surface vegetation health. The research team used correlation analysis across counties in Arkansas, Louisiana, New Mexico, Oklahoma, and Texas to determine if drought losses or health of vegetation are correlated with drought indices. This effort would validate the reliability of drought indices. 
  • Exploring Community Resilience: Given the diversity among communities, their dynamic nature, and drought duration, analyzing community resilience over both space and time could identify local weaknesses. Having this information would help prepare for and reduce site-specific challenges posed by drought. Through a modeling approach, the research team classified counties into four resilience levels, identified what factors (using social, economic, agricultural, community health indicators) were at play, and how these metrics changed in 2000, 2005, 2010, and 2015.
  • Creating Universal Models: To streamline defense against hazards, managers need strategies for assessing hazard impact and community resilience applicable across diverse scenarios. The team designed their models with inferential statistics, which allow model use in different study areas or time periods. This strategy advances efforts to develop a universal method to examine community resilience.

Project Highlights

  • Index Validity: Correlation analysis between drought indices data and drought damage data reveals indices as a valid tool to predict drought impact at county and monthly scales. 
  • Spatial Differences: The resilience inference measurement (RIM) model produces resilience scores for counties based on patterns of drought exposure, community capacity to mitigate and adapt to negative impacts, and community ability to recover. Results indicated high resilience in Texas, New Mexico, and central Oklahoma, and low resilience in eastern Oklahoma, Arkansas, and Louisiana. The spatial variance of community resilience depends partly on climatic conditions. For example, counties within ecotones had higher resilience than counties nested within distinct ecological regions. Communities within ecotones may be more sensitive to drought, resulting in a greater number of adaptation strategies. 
  • Resilience Factors: Stepwise discriminant analysis and regression analysis explain that socioeconomic and agricultural factors significantly influence community resilience level. Counties with lower employment in agriculture, but higher density of farms, scored higher in resilience than those with a high employment in agriculture and lower density of farms. This result indicates that economic diversity is important to resilience. Higher scoring counties were also more affluent and contained metropolitan areas. 
  • Resilience Disparity: Examining resilience from 2000 to 2015 revealed that resilience gaps widened over time. Counties with high resilience scores in 2000 increased resilience scores, while counties with originally low resilience scores decreased in resilience scores. Low-resilience counties may continue to decrease in resilience because they may not have the resources to recover from impact before more impact ensues.

Lessons Learned

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Policymakers should explore the resilience factors, such as those related with socioeconomics and agriculture, when devising their local and regional adaptation strategies to drought. Communities significantly reliant on agriculture economically should pursue opportunities to diversify the job sector to ensure options for community members to supplement income and maintain community stability. Agricultural communities should consider sustainable farming practices to ensure longevity of the landscape, diversifying crops or cattle, or engage in other agriculture enterprises, like agritourism, to fortify themselves when drought harms production.

102 farmers and 481 other participants from the general population in Texas were surveyed in addition to the project’s efforts. Results suggest that adoption of water conservation behaviors among them is far from universal. Survey results point to the need for educational outreach programs to increase knowledge of changing threat levels and appropriate mitigation tools to enhance the adaptive capacity of the residents living with acute and/or chronic exposure to drought.  

Low-resilience communities are at higher risk of continually declining in resilience in the wake of drought and should be prioritized in regional efforts to build community resilience. The study demonstrated that counties would grow or decline in resilience following the trends of their county neighbors. High-resilience counties can serve as resources for other counties through strategy- or capital-sharing.

Acquiring the necessary data (USGS, 2020) posed a significant challenge. The research team not only had to down-scale available data to the county level, but also ensure comparability over multiple time periods. The work’s publications make excellent resources for others aiming to reproduce similar efforts.

The interdisciplinary nature of the research collaboration synergized efforts. The team, consisting of climate, environmental, and social scientists, contributed diverse perspectives that mobilized novel ways of exploring research questions, like linking quantitative measures of drought impact to human systems with drought metrics. 

Next Steps

  • Understanding community resilience, and the factors that support or hinder it, will help communities prepare for drought and offset harm. The research team, therefore, seeks to explore opportunities to work with local planners and policymakers to develop accessible methods to use the information learned through this research process. 
  • Although the RIM model offers a sound method to examine community resilience, the research team aims to improve its ability to account for complex natural and human phenomena by incorporating other socio-ecological variables that are applicable in many study areas. These variables could include changing education level and/or diversity in farming.  
  • Drought and its impacts do not exist in a vacuum. The research team aims to expand their empirical methods to understand how drought, impact, and resilience fit into the broader story of climate change climate change
    Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.

    Learn more about climate change     , fire and fire management, human migration and settlement, and other human-nature connections.

Funding Partners

Resources

Contacts

  • Nina Lam, Professor, Louisiana State University College of the Coast and Environment: nlam@lsu.edu
  • Volodymyr Mihunov, Postdoctoral Research Associate, Louisiana State University College of the Coast and Environment: vmihun1@lsu.edu

CART Lead Author

  • Maude Dinan, Program Specialist, USDA Southwest Climate Hub: mdinan@nmsu.edu

The DLN is a peer-to-peer knowledge exchange between climate service providers and resource managers, created to gather and share lessons learned from drought events to prepare for future events. The DLN partners with CART to develop Case Studies, with funding from the National Drought Mitigation Center for interns and coordination support from the USDA Southwest Climate Hub.

Suggested Citation

Dinan, M., E., Mihunov, V., & Lam, N. (2021). “Community Resilience to Drought Hazard: An Analysis of Drought Exposure, Impacts, and Adaptation in the South Central U.S..” CART. Retrieved from https://www.fws.gov/project/analysis-drought-exposure-impacts-and-adaptation.

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