Climate Dynamics

, Volume 44, Issue 9–10, pp 2737–2750

CMIP5 projected changes in spring and summer drought and wet conditions over North America


DOI: 10.1007/s00382-014-2255-9

Cite this article as:
Swain, S. & Hayhoe, K. Clim Dyn (2015) 44: 2737. doi:10.1007/s00382-014-2255-9


Climate change is expected to alter the mean and variability of future spring and summer drought and wet conditions during the twenty-first century across North America, as characterized by the Standardized Precipitation Index (SPI). Based on Coupled Model Intercomparison Project phase 5 simulations, statistically significant increases are projected in mean spring SPI over the northern part of the continent, and drier conditions across the southwest. Dry conditions in summer also increase, particularly throughout the central Great Plains. By end of century, greater changes are projected under a higher radiative forcing scenario (RCP 8.5) as compared to moderate (RCP 6.0) and lower (RCP 4.5). Analysis of projected changes standardized to a range of global warming thresholds from +1 to +4 °C reveals a consistent spatial pattern of wetter conditions in the northern and drier conditions in the southwestern part of the continent in spring that intensifies under increased warming, suggesting that the magnitude of projected changes in wetness and drought may scale with global temperature. For many regions, SPI interannual variability is also projected to increase (even for regions that are projected to become drier), indicating that climate may become more extreme under greater warming, with increased frequency of both extreme dry and wet seasons. Quantifying the direction and magnitude of projected future trends from global warming is key to informing strategies to mitigate human influence on climate and help natural and managed resources adapt.


North America Great Plains Drought Standardized Precipitation Index Climate projections CMIP5 

Supplementary material

382_2014_2255_MOESM1_ESM.pdf (109 kb)
Supplementary material 1 (PDF 108 kb)
382_2014_2255_MOESM2_ESM.pdf (544 kb)
Supplementary material 2 (PDF 543 kb)
382_2014_2255_MOESM3_ESM.pdf (113 kb)
Supplementary material 3 (PDF 113 kb)
382_2014_2255_MOESM4_ESM.pdf (312 kb)
Supplementary material 4 (PDF 312 kb)
382_2014_2255_MOESM5_ESM.pdf (233 kb)
Supplementary material 5 (PDF 233 kb)
382_2014_2255_MOESM6_ESM.pdf (29 kb)
Supplementary material 6 (PDF 29 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Climate Science CenterTexas Tech UniversityLubbockUSA
  2. 2.Climate Science CenterTexas Tech UniversityLubbockUSA
  3. 3.Department of Political ScienceTexas Tech UniversityLubbockUSA

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