Terms of Use Staff Internal Software Web Engineering Reports Events Collaboration Visualizations Vislab VETS

Climate Change: Drought may threaten much of globe within decades

“The United States and many other countries could face a growing threat of severe and prolonged drought in coming decades, according to a study by NCAR scientist Aiguo Dai. The detailed analysis concludes that warming temperatures associated with climate change will likely create increasingly dry conditions across much of the globe in the next 30 years, possibly reaching a scale in some regions by the end of the century that has rarely, if ever, been observed in modern times.

Using an ensemble of 22 computer climate models and a comprehensive index of drought conditions, as well as analyses of previously published studies, the paper finds most of the Western Hemisphere, along with large parts of Eurasia, Africa, and Australia, may be at threat of extreme drought this century. While regional climate projections are less certain than those for the globe as a whole, Dai’s study indicates that most of the western two-thirds of the United States will be significantly drier by the 2030s. Large parts of the nation may face an increasing risk of extreme drought during the century. The study also finds that drought risk can be expected to decrease this century across much of Northern Europe, Russia, Canada, and Alaska, as well as some areas in the Southern Hemisphere. However, the globe’s land areas should be drier overall.”

- Excerpted from UCAR press release, 10/19/2010

Palmer Drought Severity Index (PDSI)

The Palmer Drought Severity Index assigns positive numbers when conditions are unusually wet for a particular region, and negative numbers when conditions are unusually dry. A reading of -4 or below is considered extreme drought. The index ranges from +10 to -10 for current climate conditions, although readings below -6 are exceedingly rare, even during short periods in small areas. By the end of the century, many populated areas could face readings in the range of -8 to -10.






Drought potential worldwide, 2000-2099



Dr. Aiguo Dai
Research Paper:
UCAR Press Release:

Tim Scheitlin (NCAR)
Ryan McVeigh (NCAR)
Mary Haley (NCAR)

Date Created:
December 6, 2010
© 2010, UCAR, All rights reserved.