10 Things You May Not Know About Drought

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Learn about some of our efforts to address the challenges of drought with these 10 examples from across the National and Regional Climate Adaptation Science Center network.

Drought can have real consequences for ecosystems and human communities alike - from leading to increases in wildfire, insect outbreaks, local species extinctions, and forest diebacks, to altering rates of carbon, nutrient, and water cycling. In the future, droughts are generally expected to be hotter, longer-lasting, and larger than those of the past, potentially intensifying these impacts. Scientists from across the country are working to understand the many different impacts of drought, how they might change in the future, and how we can better predict and prepare for these events. Learn about some of our efforts to address the challenges of drought with these 10 examples from across the National and Regional Climate Adaptation Science Center network.

1. Fighting Drought with Fire: Using prescribed fire to remove some trees and shrubs from forests may help remaining trees better survive drought events, due to less competition for water. During the 2014 drought in the western U.S., researchers supported by the Southwest CASC surveyed 9,950 trees in 38 burned and 18 unburned mixed conifer forest plots in Kings Canyon, Sequoia, and Yosemite national parks in California. They found that common conifer species in the burned plots had significantly lower probability of mortality than those in unburned plots during the drought. These findings support the idea that reduced competition may be responsible for the different tree responses, and that prescribed fire may actually make trees more resilient to other stressors, such as drought. This information will help forest management actions to impart drought resistance.

Lake Lone Chimney, Oklahoma

Drought conditions at Lake Lone Chimney, Pawnee County, OK.

2. Drought Prediction and Early Warning: EDDI, the Evaporative Demand Drought Index, is a new tool that  estimates the changing “thirst” of the atmosphere and can provide early warning of drought emergence and persistence. A team of climate scientists working in collaboration with the North Central CASC, University of Colorado, and NOAA’s Physical Sciences Division at Boulder took part in developing EDDI, which could improve our ability to predict and understand rapidly-evolving, shorter term “flash” droughts and indicate the persistence of longer-term, ongoing droughts. EDDI has already been successful in signaling the onset of drought in several different locations in the U.S., including in the Northern Great Plains in the summer of 2017 and at the Wind River Indian Reservation in Wyoming in 2015.

3. Science for Farmers and Ranchers: Many farmers and ranchers depend on science to monitor, understand, and prepare for droughts, yet the available science does not always fully meet their needs. Climate variability and drought can have significant impacts on agricultural production, currently valued at over $44 billion dollars annually in the South Central U.S. Researchers supported by the South Central CASC recently assessed the information needs of farmers and ranchers in the region and developed a new science product that utilizes precipitation and evapotranspiration data to indicate and measure the occurrence of drought. This work helps to improve the usefulness of scientific information to on-the-ground decision-makers and ensure that important agricultural decisions are based on sound science.

4. Slowing the Flow: In the northeastern U.S., increasing water storage in natural areas could protect water resources, infrastructure, and ecosystems from drought. In the Northeast, more precipitation doesn’t necessarily mean fewer droughts. Increases in temperature could outweigh potential increases in total precipitation, resulting in more frequent and intense droughts. Researchers with the Northeast CASC are assessing a “slow the flow” watershed management approach for the region, which focuses on increasing water storage in natural areas via actions such as the reconnection of floodplains to rivers, conversion of impervious surfaces to forests, and beaver management to encourage dams and natural impoundments. This approach can decrease the vulnerability of water resources while also providing benefits for ecosystems, fish, and wildlife.

5. Snow Drought: In Arctic and sub-Arctic regions, “snow drought” can manifest in several ways, including changes in total snowfall amounts, snow accumulation, and the timing and length of the snow season. Snow drought can have significant effects on the health and function of ecosystems, yet little research has been conducted to understand these impacts in high-latitude areas. Researchers supported by the Alaska CASC are exploring ways to predict the occurrence of snow drought and are determining how land cover and terrain affect the susceptibility of an area to snow drought. For example, the researchers are using various observational and remote sensing datasets to understand how the occurrence of landscape changes, such as fire, can impact snow accumulation and melt.

Image: Drought Effect

The white colored rock (approximately 100ft high) shows the drop in the water level of Lake Mead as a result of the ongoing 10-year drought along the Colorado River. Credit: Guy DeMeo, U.S. Geological Survey

6. Future Water Availability: As temperatures rise and droughts become hotter and longer-lasting, estimates of water flow in streams are critical for informing decisions about water availability for both human and ecological needs. Resource managers are making complicated water allocation decisions in the face of competing human and ecological demands and uncertain future temperatures, precipitation patterns, and land cover changes. Researchers supported by the Southeast CASC developed a model to help managers understand how watersheds and water availability in the Southeast might be impacted by changes in climate and land cover over the next century. This information can inform the development of adaptive strategies that address water availability and needs under possible future scenarios.

7. Drought Refugia: Some areas, known as “drought refugia”, may experience fewer changes in climate or show increased resilience to these changes, compared to surrounding landscapes. These areas can act as havens for wildlife, as temperatures and precipitation patterns change, and may become increasingly important to many wildlife communities as changing climate conditions alter the frequency, duration, or severity of drought. Researchers supported by the Northwest CASC have undertaken an effort to identify areas of refugia in the northwestern U.S. These scientists analyzed different landscape characteristics from satellite images of southeastern Oregon and found that some spring-fed wetlands, such as those located below persistent snowbanks, may be particularly resilient to changing conditions.

8. Fog Drip and Drought: During periods of drought in Hawai‘i’s rainforests, fog drip, the process by which water droplets accumulate on the leaves and branches of plants and then drip to the ground, can act as an important source of water. Also known as cloud-water interception, fog drip provides moisture for plants, reduces wildfire risk within the fog zone, and contributes to groundwater. Researchers supported by the Pacific Islands CASC are estimating how reductions in water availability during drought may be offset by fog drip within the fog zone, potentially reducing the impacts to plants, soil moisture, and groundwater. The results from this study can inform Hawai’i’s water, forest, and wildfire managers, as well as farmers and ranchers.

9. Drought in Dryland Ecosystems: The productivity of many plants in the southwestern U.S. is already limited by water availability, making them particularly vulnerable to increases in temperature and changes in precipitation. Widespread declines of multiple plant species have already been observed, providing insight into what the future could look like for vegetation in the region as conditions are projected to become warmer and drier. Scientists supported by the National CASC recently worked to understand the vulnerability of dryland ecosystems to drought in the Southwest. Researchers found, among other results, that shrubland and woodland plant communities in the Colorado Plateau maintained greenness under sustained water deficit longer than grasslands. This information can help managers determine which plant communities might be more vulnerable under future climate conditions.

WERC Hotter Droughts

Extreme effects of drought on Forests. Credit: Nathan Stephenson.

10. Drought Impacts from Leaf to Landscape: California’s recent droughts can provide insights into the effects of “hotter” droughts on forests, from “leaf to landscape”. “Hotter droughts” (otherwise normal droughts whose effects on ecosystems are exacerbated by higher temperatures) are an emerging threat to forests, particularly in the Southwest. Researchers supported by the Southwest CASC examined the impacts of drought on Sierra Nevada forests at three scales: individual trees, tree populations, and forested landscapes. They used California’s unusually hot drought as a potential preview of the future, collecting information that will help guide forest management as temperatures warm. Results include the finding that giant sequoias exhibit both leaf- and canopy-level responses during droughts to reduce water loss and that very few sequoias died during the droughts compared to other tree species. This information will help forest managers target forest treatments – such as prescribed fire – aimed at increasing the likelihood that forests will persist as climate conditions change.

Learn more about our work on drought across the country here.

This year, 2018, marks the 10-year anniversary of the establishment of the National Climate Adaptation Science Center (NCASC; formerly named the National Climate Change and Wildlife Science Center). In those 10-years, the eight regional Climate Adaptation Science Centers (CASCs; formerly named the Climate Science Centers) were established. Together, the National and Regional CASCs funded over 425 science projects and built a network of research partners, resource management stakeholders, interdisciplinary staff, fellows, and early career researchers.

In celebration of our work and accomplishments over the last 10 years, we have launched a monthly series featuring “10 Things You May Not Know” about different topics our science has focused on, including drought, glaciers, and wildfire. Stayed tuned next month for the next part in the series! Learn more in the posts below:

10 Things You May Not Know About: