Droughts and Climate Change

How does Climate Change Impact Droughts?

Defining drought may seem easy. If an area receives less rain or snow than expected over the course of a year, it can be classified as being in drought. The severity of drought increases over time depending on how long an area remains arid. However, there’s more to the story than solely if there isn’t enough rain or snow.

Droughts don’t just affect water stored in wetlands, lakes, and rivers, but also water below ground stored in aquifers and in the soil. When this groundwater gets used up, the dry ground can act like a sponge, sucking surface water straight in. The surface water-groundwater relationship gets even more complicated with snowpack. If snow melts too early in the year, water can move through the environment too quickly, causing the ground to dry up and become “thirsty” too soon. So even if there is “enough” water, the timing of the water may dictate whether an area is in a drought.

Climate change has further altered the natural pattern of droughts, making them more frequent, longer, and more severe. Since 2000, the western United States is experiencing some of the driest conditions on record. The southwestern U.S., in particular, is going through an unprecedented period of extreme drought. This will have lasting impacts on the environment and those who rely on it.

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USGS Science Helps Communities Understand, Prepare, and Mitigate Droughts

The USGS employs its wide range of scientific expertise to study how droughts affect human and natural communities and how to effectively predict, prepare for, manage, and recover from water shortages. USGS research spans geographic and temporal scales, exploring everything from short, local “flash” droughts to long-term, large-scale “mega” droughts.

Our science helps to:

• Understand how climate change contributes to modern droughts
• Explore the effects of droughts on plants, animals, ecosystems, and communities
• Help develop water management strategies under drought conditions
• Develop tools to assess the severity of droughts and to predict future droughts
• Understand the connection between droughts and wildfires
• Use the fossil record to compare past droughts to current ones

USGS Data, Science, and Prediction

The USGS actively coordinates our drought research efforts among our many diverse scientists. Experts like water scientists, wildlife biologists, and geologists all work together to study droughts and their impacts. This effort strengthens our existing observation networks by investing in real-time data collection on rainfall, stream flows, and environmental impacts. With these improved data sets, USGS scientists are working to better understand when and how droughts occur. We are also developing models to help predict which communities and landscapes may be vulnerable to future droughts, as well as when, how long, and how severe those droughts might be. We provide this information to help cities and natural resource managers develop plans to prepare for future droughts and lessen the impacts of droughts on natural and human communities.

Additional Resources

• Current Map | U.S. Drought Monitor (unl.edu)
• National Current Conditions | Drought.gov
• Climate Prediction Center - United States Drought Information (noaa.gov)