Last updated October 10, 2018

California Getting Wetter to the North, Drier to the South: Natural Variability or Climate Change?

  • States that current climate change projections anticipate that global warming trends will lead to changes in the distribution and intensity of precipitation at a global level
  • States that few studies have corroborated these model-based results using historical precipitation records at a regional level, especially in California
  • Analyzes 14 long-term precipitation records representing multiple climates throughout the state
  • Finds northern and central regions increasing in precipitation while southern regions are drying
  • Finds that winter precipitation is increasing in all regions, while other seasons show mixed results
  • Finds that rain intensity has not changed since the 1920s
  • Finds that while Sacramento shows over 3 more days of rain per year, Los Angeles has almost 4 less days per year in the last century
  • Finds that both the El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) greatly influence the California precipitation record
  • Concludes that the climate change signal in the precipitation records remains unclear as annual variability overwhelms the precipitation trends